No, developing PRACTICAL transwarp beaming implies this. It is never stated that the technique was ever developed into something practical, and in all probability, it wasn't.
But for all intense and purposes, Spock handed Starfleet in the 23rd century the formula for practical TW beaming.
No, he handed them the formula for SUCCESSFUL transwarp beaming. The ability to do something a small number of times under special circumstances does NOT translate into the ability to do something any time you want as often as you want. That is the difference between "practical" and "possible."
With current technology it is POSSIBLE, for example, for the U.S. Marine Corps to insert troops into the battlefield using space capsules riding on the tips of ballistic missiles. In fact, more than possible, that would be cool as hell; the Pentagon gets a call about a terrorist hijacking somewhere and literally ten minutes later you have a platoon of Marines (ODSTs?) dropping out of the sky in wingsuits, ready to kick ass.
But is that a PRACTICAL way of deploying special forces troops into the battlefield? There are problems with that technique that have nothing to do with the technology involved; issues of G forces on the human body, the probability of reentry system failure, the fact that you can only deliver a very small number of troops this way, the fact that your troops will be very exposed to ground fire on the way down, and the fact that the time it takes them to reach the ground from parachute altitude gives away any surprise advantage. That before you consider the COST OF THE ROCKETS being ridiculously high just to insert a few dozen soldiers behind enemy lines.
I've noticed Trek Tech watchers sometimes struggle with analogies, so to break it down further: You can use transwarp beaming to move a person from one place to another, but if the technique is dangerous, financially/energy expensive, or if the benefits of using it outweigh the inherent risks (e.g. the possibility of materializing 500 feet above the surface of the planet you're beaming to) then its practicality will be relatively low. In short, transwarp beaming may well be the FASTEST way to move a person from one planet to another, in much the same way that an ICBM is the fastest way to move a person from one country to another. But we have seen nothing to suggest that this is the safest, most reliable, or even most effective way to do that.
Which is why Starships wouldn't likely be obsolete as HISHE tried to imply.
You would ideally scan the planet from a nearby planetary system with regular sensors...
Even in TNG, detailed scans of planetary systems usually require a starship to close to within a couple of light seconds or closer. Probes are used when the starship can't get that close itself, and THEY have to get within a couple of light seconds.
Uhm, I don't think radiotelescopes and subspace sensors are the same thing.
Neither are radiotelescopes and REGULAR telelscopes, but both have similar limitations of resolution and range.
And what is a subspace telescope if not a radiotelescope that operates via subspace radio?
Whatever you can see through them on the other end, it will likely be enough to get a 'general idea' of an area - and it would be far more detailed and informative than a radiotelescope could ever hope to provide.
It would certainly be FASTER, that is, your long-range sensors would be able to image objects tens of light seconds away with no time delay. They could probably also take realtime radar maps of planets and asteroids from the other end of a solar system and not have to wait several hours for their scanner beams to bounce back to the ship.
But nothing about subspace radio or subspace itself suggests their sensors would be MORE DETAILED at that range. TNG dialog frequently refers to their most detailed sensors as "multi-spectral" devices. Which is good, because that's basically an evolution on real world science sensors on JPL space probes: you send some kind of radiation signal at the target, the signal causes the target to fluoresce (harmlessly, in most cases) and your sensors read the returning radiation pattern. "Scanners" of all types seem to work this way, even the weirdo alien scanners that light up the entire room when they're being used (and are the futuristic equivalent of high-resolution lidar or millimeter-wave radar imaging).
But scanning is always done at close range: You have to get close enough to something to see it in any detail, let alone examine it. How close you have to get depends on how big the thing is that you're looking at/looking for. If it were possible to take those kinds of detailed readings from a distance, the Federation wouldn't build starships, just a lot of really huge telescopes.
Let's not forget the NX-01 sensors in the 22nd century were able to read DNA on an alien ship which was at FTL and millions/billions of km away.
And yet they couldn't tell if there was anyone still
alive on the Axanari ship from 5km away.
Enterprise, like Voyager, is probably not something we should take seriously.
Doing the same to gain at least a baseline biological analyses would be more than doable over multiple lightyears in the 23rd century
Since when? They were never able to do this in TOS. Those kinds of surveys were usually conducted IN PERSON, using tricorders and physical samples; they couldn't even collect that kind of data from near orbit.
Indeed, but the resolution of sensors in the 23rd century would likely be far superior than those on the NX-01 when scanning lightyears away
That's pretty doubtful. If narrow a scanning field to one arcsecond of the sky, and scan out to one light second, your scanning field is a patch of space over 80 kilometers across. You could probably fire all kinds of impulses and flood that patch of space with radiation and listen for a return that would indicate that something in that 80km slice of the sky contains what you're looking for; then again, that's an 80km patch of sky, so to get a weapons lock or a transporter beam on the target you have to narrow the field DRAMATICALLY.
That same scanning field projected out to one light year would cover a patch of sky two point seven billion kilometers across. In other words, the entire solar system inside the orbit of Uranus. ASSUMING that you are able to produce impulses powerful enough to get legible responses at that distance (and that is a hell of an assumption with exactly zero support for starships) then IF your sensors can pick out the return signal from background noise, the only thing they've told you is that the thing you've detected is
somewhere within 20AUs of the center of your scan field.
What's more, at this distance there's going to be an upper limit to what is and isn't detectable. An individual life form isn't going to radiate more energy than the surrounding environment, unless you light him on fire or do something similarly dramatic to cause him to stand out from the background. Most starships probably won't either unless they are in cold interplanetary space with their engines running hot. And once again, your sensors will be able to tell you the ship is THERE, but they won't be able to pinpoint its location or get a good image of it (or possibly even IDENTIFY it).
This is mainly why detailed sensor scans ALWAYS require a close approach by a starship. It isn't ONLY the incredible vastness of space that's a factor, it's the fact that the human definition of "detailed" includes things that exist on such a scale that they would not be detectable against the background of wherever they are UNLESS you hit them with enough energy to split their atoms and vaporize them.
Not necessarily life forms, but it would likely be able to ascertain whether a planet is class M or not, and general conditions on the planets' surface
We can almost do that with CURRENT sensors. As far as I can tell, the only difference between Starfleet sensors and modern NASA devices is Starfleet sensors operate faster than light, are a lot smaller, and they carry way more of them.