You have no evidence to declare that.
They included a scene where Burnham exhaustively described in detail how the cloaking device actually works, something which no character in Star Trek has ever actually done. So it's clear that THEY do not think the scene in "Balance of Terror" works the way it was originally written or filmed. Cloaking devices aren't theoretical at this time and have LONG since moved to "practical applications."
Anyway, ENT clearly connected them, intentionally, and you still deny it
ENT alluded to it the same way "Friendship One" did, but ENT didn't establish UESPA as being "the authority" that oversees Starfleet. Again, Friendship One clarified that (somewhat) by saying UESPA was the organization that operates unmanned probes.
just as you deny DSC being a prequel to BoT as it is intended.
If it was a prequel to
Balance of Terror, the antagonists would be Romulans, not Klingons.
Sorry to get all "bro do u even lift" on you here, but I happen to be an English major who has worked for years as a certified tutor teaching people the English language at the college entry level. Your statement is incorrect.
And was an English major and for years worked as a technical writer, public relations specialist and on a daily basis have to coordinate with various people and businesses using spoken and written communication. Word choice matters, and using words incorrectly can make people angry and confused. I am telling you from EXPERIENCE that this is not the way "theoretical" is actually used in any industry I'm aware of and even in day to day conversation it creates confusion. (e.g. "What do you mean ' theoretically'? Does it work or not? Give me a goddamn straight answer!" vs "Is that theoretically possible? If so, can you give me a cost estimate?")
Making a fortune is theoretically possible through winning the lottery...
Strictly speaking: one would say "winning the lottery is theoretically possible through actions X, Y, and Z." That is, if you have a one in 45,000 chance of winning the jackpot, then theoretically you would win the lottery IF you played it 45,000 times, or if you bought 45,000 tickets at once. A few years ago there was even a group of enrepreneurs who put that theory to the test when they figured out how many lottery tickets they would have to buy to gaurantee a win, weighed against the cost of those tickets and the actual jackpot.
"Theoretically possible" can be spoken as a colloquialism in the way you're using it -- e.g. "Falling off your bike is theoretically possible" or "Getting gonorrhea is theoretically possible" but that's not what that term actually means. "Theoretical" in this usage is contrasted with "practical." Meaning "in theory" vs. "in practice." It is in this sense the term is generally used, and it is in this sense that Spock is actually speaking.
As if there was ever any doubt. This is
Spock we're talking about.
In fact, anything and everything that has ever happened anywhere at any time, but cannot be said for certain to in fact be happening in a given place at a given moment, is theoretically possible.
No, it is not. Again, there's a difference between "practical" and "theoretical" knowledge in most contexts. A "theoretical invisibility shield" can be spoken of in terms of thought experiments, models, simulations, etc. A
practical invisibility shield is something that someone actually builds and has demonstrable, quantifiable characteristics that may differ substantially from the theoretical models.
It's important to note that this difference is meaningful because something being possible in theory doesn't mean it is doable in practice; the conditions that exist in the theoretical model may never actually manifest, and so the theoretical concept never becomes practical. In this case, it would be unusual to speak of "theoretical" possibilities for something whose practical applications have been demonstrated conclusively for over a hundred years, especially in light of Spock's line that implies the major obstacle to said applications:
"Invisibility is possible with selective bending of light, but the power cost is enormous. They may have solved that problem."
Here, too, is another problem: we know the Romulans solved this problem in a relatively mundane way, by equipping their ship with an enormous power generator that eats fuel like you wouldn't believe. This same generator also fuels a ridiculously over-powered plasma cannon capable of destroying small moons with a single shot. But the power costs have not been the major problem for most other applications of the cloaking device, mainly due to successive shows recognizing that FTL travel takes a lot of power in the first place and this wouldn't be a problem for a starship. It certainly doesn't seem to be a problem for the Klingons, who never make any mention of the cloaking device consuming too much power or too much fuel or whatever else might allude to power consumption. They can't fire while cloaked for some OTHER obscure reason that isn't made clear.
Once again, to be clear: I am not disputing that the writer of "Balance Of Terror" meant the line to be taken as you suggest, nor that in the absence of evidence to the contrary this would be a logical implication or inference to draw from it. I am disputing the premise that even in light of exactly such contrary evidence, it cannot be taken any other way.
That's a silly thing to dispute, considering that is exactly how the line is supposed to be taken AND the fact that the context of the scene clearly supports that interpretation. Taken IN CONTEXT, you would have to take Spock to mean literally anything OTHER than what he actually says.
In which case, I'm not even sure what your point is. You're basically conceding that -- in the context of broader canon -- Spock couldn't possibly have meant what he actually said, or meant what he obviously meant. So rather than try to put words in his mouth with some sort of bullshit semantics gymnastics, we're better off just chalking that up to a retcon and saying "When the show was filmed, that was the intent. Later episodes contradicted this." We don't need an in-universe rationalization for the line; we have all kinds of interesting headcanon ways we can explain it without having to pretend it actually works in context.
Because, objectively, it DOESN'T work in context. Fans are really good at taking things that don't work and making them SEEM to fit, but that doesn't make it any less broken.