There was an in-universe time gap, and none of those things *undo* what came before it; They add realistic arcs and advancements. Ship was refit blatantly in dialogue. Kirk had been through some stuff and had a personality shift / arc for the movie. Klingons were explained on ENT. It may have been change for the sake of change, but since it was advancing into a new part of the timeline, it didn't break anything that came *before* it the way Discovery breaks things both forward and backwards.
Discovery doesn’t “undo” anything; discs of old episodes didn’t suddenly self-destruct as it aired.
Trek is full of retcons and inconsistencies.
Try head ridges on Romulans both before and after TOS (contradicting a key plot point in Balance of Terror), First Contact retconning BoBW, displaced Bajora vs occupied Bajorans, Trill with ridges who can’t transport vs Trill with spots who can, Vorta mind powers, etc.
It’s particularly amusing that Spock’s line about no previous mutinies is cited in this thread to show that Discovery is inconsistent. Spock’s line itself is inconsistent - there had been two previous mutinies on TOS alone; he was the mutineer in one of them!
Funny how some are willing to handwave past inconsistencies - oh hey, this was explained in a half-arsed way 35 years later so it’s okay - while being OUTRAGED by Discovery.
I've seen people (the same ones who, ironically, were the first to bash ENT back in the day and demand for Berman and Braga's removal as showrunners and who now demand for them to come back) say "At least they TRIED with Enterprise! Discovery doesn't even TRY anymore and is therefore much worse!".
I have old fanclub magazines filled with complaints about the Trek shows at the time - DS9 isn’t Trek, Voyager is TNG-lite, Enterprise is destroying canon, etc. Hell. i stopped coming here for years because the Voy & Ent bashing was so constant.
Yet now when many people want to bash Discovery, all of previous Trek is one big amorphous lump and Discovery is somehow ruining it all (just like the Kelvin films were a few years before).
It’s the most tedious fanbase I’ve ever been a part of.