The PLANET OF THE APES tv series in 1974 had played kinda fast and loose with the movie continuity. Ditto the LOGAN'S RUN tv series. I think there was less of an expectation in those days that everything had to fit into one seamless "canon" or continuity.
Except most things like that -- TV adaptations of movies -- are meant to be in their own separate continuities. The
Logan's Run TV pilot was essentially a semi-remake of the movie, a new start of a parallel story rather than a continuation. (After all, they needed the city authorities to be an ongoing threat, which the end of the movie precluded.) POTA was the same way -- it wasn't a sequel to the movies, but a reboot that borrowed bits and pieces from the movies (most notably the ape makeup design, which was iconic and state-of-the-art for the day) and put them together in a different way. The only character they had in common was Dr. Zaius, and he existed centuries earlier in the TV show than in the movies, in a world where humans were verbal and civilized instead of mute "animals." There was a reference to prior astronauts having visited the apes' time many years in the past, but it didn't map onto the specifics of the movies (obviously, since the world blew up within a year of Taylor's arrival).
Even in cases where the TV series is supposed to be a sequel to the movie rather than a reboot, they almost always change things from the movie to fit the needs of the show.
Starman retconned the movie's events from the '80s to the '70s so the title character could have a teenage son in the present day.
Stargate SG-1 totally reimagined the aliens, modified the workings of the Stargates, tweaked the lead character's name and personality, moved the SGC from Creek Mountain to Cheyenne Mountain, etc.
Men in Black: The Series, in animation, totally ignored the ending of the movie and had Agent K still on the team. Plus there are a couple of borderline cases that changed things from the movies, but in ways that could be reconciled if you squint a little, like
War of the Worlds: The Series, RoboCop: The Series, and
Alien Nation.
Star Trek, though, is something different from those cases. It started as a TV series, then spawned movies with the TV cast, presented as (loose) continuations. That was something that was done occasionally in the '60s (
Dragnet, Batman, Munster Go Home, A Man Called Flintstone, etc., plus overseas feature films re-edited and expanded from TV episodes, like the various
The Man from UNCLE movies -- not to mention '40s movies based on and starring the casts of radio shows like
Fibber McGee and Molly and
The Great Gildersleeve), but what happened with Trek was perhaps unique at the time, in that the original-cast movies continued past the first and eventually spawned a TV revival in turn. I guess it was that precedent that led to TNG being a nominal continuation rather than a reboot -- though Roddenberry did approach it as a soft reboot, discarding a lot of the mistakes and disappointments he saw in TOS and the movies. It was his successors, many of them fans of TOS, who brought in stronger ties with TOS continuity and solidified the idea of it all as a unified whole.
Even Star Trek. "The Enterprise Incident" presents the cloaking device as something new, when it was originally seen in "Balance of Terror" (though I always attributed Spock's line that 'they appear to have a new cloaking device' to mean a new, improved version, not necessarily something never before seen).
"Incident" didn't portray the cloak as new, just improved. Spock said "I believe the Romulans have developed a cloaking device which renders our tracking sensors useless." Meaning that it was an improved cloak that couldn't be tracked using motion sensors like the one in "Balance of Terror." Although audiences who didn't remember "Balance" could easily interpret the line to mean that cloaks were new.
It seemed starting with the later seasons of TNG continuity became more important. DS9 and Voyager were largely build on continuity. So I think we started expecting it. Enterprise went to a lot of trouble in the 4th season to tie things together in as nice a bow as possible. Then Discovery came along and decided they weren't going to play by the old rules and I guess some of us were just jarred by that.
Honestly, I think
Discovery is even more obsessed with Trek continuity than ENT season 4 was. Sure, it changes superficial appearances and the occasional detail of interpretation (warp drive being far faster, Harry Mudd being a mass murderer), but it was overloaded with stories that drew on prior Trek continuity and revisited old ideas rather than telling new stories. Spock's sister, Sarek, Klingon death screams, tribbles, a Gorn skeleton, Harry Mudd, the Mirror Universe (oy, so much Mirror Universe), the whole season is built around continuity porn. Not that that couldn't produce good results -- "Lethe" is my favorite episode yet, and it's all about revisiting "Journey to Babel" and filling in the blanks in the Spock-Sarek relationship -- but it's way, way overdone compared to most Trek shows.
Indeed, I'd submit that the show's constant reliance on pre-existing Trek elements is
why it seems to have so many contradictions. If it had fewer continuity nods and relied more on telling new stories, then the discrepancies wouldn't be as frequent. So DSC is
very, very much trying to tie things together, to say new things about old bits of Trek continuity. Far too much so for its own good, if you ask me. It's just not as precise about the surface details.