Lets take a look at Fighters in Star Trek before we move on to Drones and try and keep it to Star Treks fiction technology, IE Banking included (probably a gravity bubble or something). As stated in the Article they are not Airplanes they are Spacecraft like every other Spacecraft just smaller, Fighter is just a designation.
So we will start with several so called Fighters, small ones not like Jem'Hadar ships but 2-5 crew.
Federation Attack Fighter
Facts about these ships systems.
They are slower then bigger ships with bigger engines and less maneuverable then bigger ships with more Thrusters. They are not out running the Enterprise D, don't know about their maneuverability comparison.
They are no more accurate then bigger ships using the same weapons designs. Take the Phaser Array off a Runabout and upsize absolutely everything about it by 500% and it will be just as accurate and much more powerful on a Galaxy class. Photons would or could depending on their design be more accurate and faster if bigger, more fuel, more thrusters, bigger engines, ect.
Smaller can make them harder to hit as well but with good tracking systems it isn't the biggest advantage since a well designed big ship can aim as well or better.
So now it is looking like bigger is better... it is, it so, so is.
So why build the so called Fighters. Resources for a start, can't just build ten new Excelsior's for every Backwater Sector that needs Patrol for shuttle sized Pirates when Attack Fighters or Runabouts would do fine at 1/50th the cost. If a Bird of Prey comes along, time to get on the horn for support.
Okay lets move to the scene where a dozen or so "Fighters" take on Gul Evek's Galor class Medium Cruiser. Now the Galor has a higher warp speed so it should by all means be able to say see ya noobs and warp off, but what if the Warp Drive was hit since damage as everyone knows leaks through the shields, or a graviton pulse, or spacial anomaly or whatever.
Still Faster at Impulse but Phasers and Photons have ranges in the hundreds of thousands to millions of kilometers so perhaps he didn't have the time to escape at impulse and decided to fight it out. They were also flying suicidally close, as any Jem'hadar about to smash his Attack Ship into a Galaxy class could tell you, ramming your way through smaller ships is a bad idea that leads to your bigger ship exploding. Shields react badly to ship impact.
Okay then so his ship is bigger then all of them combined, why isn't it winning? Well it is a medium multi-mission cruiser designed for long term deployment, operating months to years in space and expected to do fifty different things, let us see what that entails. Well you have more crew. Fighters are crewed by 2 to 4 people on short range missions. Big ship so you will want an engineering staff to maintain it for months. Command staff and secondary watch staff. Ship Security. Science Teams even if they are small on a military ship to analyze / defend against new discoveries, spacial anomalies and such. Medical teams. Troops because even if they are not carrying them the ship is designed too.
What does that big crew entail and what kinds of systems would big multi-mission ship Galor class probably (speculation) have that a small fighter wouldn't.
* Big Cargo Bays to take on or carry supplies, spare parts, weapons, vehicles ect.
* Huge Turbolift system, big ship so you have to get around quick.
* Bunks for the hundreds crew and their night shifts, ground troops, guest quarters, ect.
* Shuttle Bays because the first officer has a briefing in Chintoka while the ship is heading to Monet and twelve guys have shore leave on Cardassia four.
* Mess halls, meeting rooms, entertainment facilities (Stir crazy, no).
* Large Medical bay / triage rooms ready to accept large scale military casualties. With crack med staff and lots of supplies for all ailments physical, chemical and biological.
* Like Six or so Transporter Rooms for beaming up and down troop formations and large cargo.
* Extra Fuel Bays for a long Voyage.
* Internal Comm System and External Comm to support hundreds of people.
* Food / Water, Wash and Waste Facilities and matter for replicators.
* Jefferies Tubes or the Cardassian equivalent for maintenance.
Now Fighters are cramped, their single transporter pad is a half a closet at most. Galor class would have whole big rooms for that, more spacious hallways, everything would be bigger for long term comfort. Life Support which is confirmed to suck a lot of power would be so much higher then a ship designed for 2-5 guys.
How does the small ships do it. Automation. Their is no engineering team to fix the warp core, how to maintain it is hope nothing bad happens to it. Photon Tubes and Phasers are automated, if a consul overloads on a Galor there are back ups consuls, if a coupling or coil or emitter is damaged use a back up or fire through another emitter or even call a repair guy. Not so much on a Fighter.
Pound for pound the fighters could overwhelm big ships with numbers in the right circumstance because their ship is direct combat focused. So if bigger is better why not just build a bigger Warship with minimal crew facilities, lots of automation, no luxuries and designed for nothing but space combat...
Yeeeah the Defiant. In the combat weight class of Excelsior's and Galors at a third the size and it smashes Marquis Raiders into mulch with ease. Can't do much of the other stuff those big ships can but it can kill them fine. The Prometheus is an even bigger Defiantish type warship that smashed a Warbird to pieces. So why build small ships, cost and bigger is better but impractical for smaller tasks. The Marquis and Bajoran Resistance also don't have the money / resource to build a Battleship but give them a good size replicator and they can run out new Fighters or buy them from anyone who can. It is all about picking targets and ambushing in swarms. Fighting on the run never face the enemy head on until you where them down or catch them off guard.
Why / Why not?
Well lets say it is launching little impulse ships. The faster enemy ship moves out of range with bigger engines, picks them off with longer range bigger weapons. Or the bigger ship goes to warp, you can't pursue because the Carrier needs to pick up the smaller craft and they get away. Say the Carrier does pursue, half its firepower is in the launch bay and it is outgunned fighting at warp. Something that would not have happened if those were phaser power cells and not useless impulse craft.
So give them warp engines? Okay now they are bigger none of which goes to shield, impulse engines or weapons, now you you carry less of them or need a bigger ship to carry them. Can they reach warp 9.8 like the Carrier or the enemy ship... no, crap. Again wasted space that could have gone to weapons on the bigger, faster, stronger now not a Carrier. That and every Fighter destroyed is firepower lost that the big ship would still have. Often shorter range firepower then coming from a bigger ship.
So are Carriers useless? Let's look at a couple of designs that could work.
* A fleet tender that refuels, rearms and repairs warp fighters for sector patrol when there are no nearby Starbases. Not a real Carrier per say but does a similar job.
* A ship big enough to carry them all so they can all respond to a sector in trouble at warp nine. Internal Maintenance Bays for extensive repair on long deployment and rest facilities and resupply for the crew. Basically a mobile Starbase.
Okay they can help cover more ground then a single powerful warship when a single powerful warship is not needed for tiny threats. It is still at a disadvantage vs a real warship that is better in every way like a Defiant type design of equal size to a Carrier in battle but that isn't its purpose. Not a ship you would want on a Battle Fleet when real ships are available but a ship you would want defending an entire sector from small threats.
* Communication jam = loss of ship.
* AI control, now you are getting into Skynet territory or deadly malfunctions.
* They jam you and take over the link, you just lost a fleet of ships to the enemy, if you have access they can get it, if you don't have access then you don't control the AI (see above).
* Situations that require diplomacy are not best left to computers that don't look at negotiation when assessing the ship attacking. Good job starting a war instead of talking it out Drone.
* No loss of life.
* No life support drain.
* Faster reaction time.
So what is the biggest reason ships are not automated... they are all automated. You target Phasers you are not shooting from the hip, the computer does it. No steering wheel, you can ask for complex courses and the ship even has an autopilot, it does all the calculations for both. They are already automated to the hilt, they just have a sentient crew punching in the commands.
Why do they do that? Well most races are shown to be more comfortable with a crew in charge of the weapons. A little less reaction time is fine to them and what is 200 lives of people willing to give their life on a Star Cruiser vs two billion on a colony if the enemy takes control of the drone or it goes haywire.
Do Drone Ships work, yes. The Romulans did it to try to keep their identity secret and those tiny ships outclassed bigger crewed ships like the Kumari. Also Starfleet took control of it.. but whatever. Also the Prometheus was automated and destroyed a Warbird with only 2 AI Holograms controlling three pieces of the ship from one piece of ship, so Automation is good even with a small crew, also the Romulans took it over... before Star Fleet took it back.. but whatever.
Yes Automation, Command Links and AI work, no they are simply not comfortable doing it all that much. They are willing to spend the extra nickle to train a crew and make the ship life friendly.
Drone Ships can and probably would win a war over life ships pound for pound if they are not compromised for sure, no one is as of yet willing to take a big risk on that though with their fleets.