Well, don't forget that there were fighters in Trek, albeit not seen until part way through the Dominion War. My personal speculation as to why they didn't appear earlier is that it wasn't until then that technology could be made compact enough to make such a small vessel into an effective combatant. Maybe a spin off from the development of runabouts.
Exactly. The existence of runabouts (and fighters) would be evidence that by the late 24th century there is enough compact technology for a starfighter to be able to attack, defend and maneuver against starships.
You can see the progress from TOS thru DS9.
In TOS, a small Orion ship could be modified to overload its engines to put maximum power into phaser strikes while retaining superior mobility. Still, she didn't have enough power to adequately stop a single phaser strike ("Journey to Babel").
In TOS Movies, a BOP was still no match against the Enterprise (as evidenced by Kruge's comments) and it was only luck that the Enterprise was already crippled that led to her loss in "The Search for Spock". Even a "fire-while-cloaked" BOP in "The Undiscovered Country" was only able to score so many hits on the Enterprise because she
had to stop an assassination. One hit on the BOP rendered it disabled or destroyed. If it were a general battle, the Enterprise would've just left the area, regrouped and found a better strategy.
It is not until TNG, where we see groups of smaller craft (the Maquis) to be able to stay in a fight long enough to be able to deliver damage. DS9 furthered that with fighters surviving hits from Dominion-boosted Cardassian warships. That's the best evidence that fighters by the late 24th century are able to fight alongside and against the big ships.