I think people reach different breaking points. TNG, DS9, VGR, and ENT, while somewhat different, were all basically made for the same audience with the same guardrails. Many people likely came in knowing each series took a while to get good. Many wanted to give early DISCOVERY the benefit of the doubt after not having a Star Trek series for over 10 years, that things would eventually make sense within the wider continuity, and that the producers would somehow "come to their senses". Instead, while some fixes were made, many other things actually got worse. And soon it was very clear DISCOVERY was made for a very different audience, and many things would never change.
On the other hand, it must be weird for the DISCOVERY fans to run into arguments again and again frozen in time from 2019 from the point many did finally jump ship.
And of course PICARD season 1 was its own descent into increasing polarization. I didn't get around to watching it until just before the premiere of season 3.
For people whom came to being fans of
Trek during the 90s, it seemed like Berman-era
Trek had this unofficial rule (starting with TNG) that the different series usually took some time to figure themselves out. There are individual episodes in the early years one can point to, but usually it's season 3 before TNG was considered "good," seasons 2 and 3 are considered the turning point for DS9, it's season 3 and the Xindi storyline of ENT before they get the dynamic of Archer right, etc.
And, to a degree, I think I saw the early issues with
Discovery through that prism, of growing pains where I expected them to course correct into something more enjoyable. But I think
Discovery fits more with modern shows, where unless there's a drastic change when switching from showrunner to showrunner, there's not going to be a change reflected in what you see on the screen. The tone and type of storytelling are NOT going to change that much, only tweaked a little here and there.
Here's a likely controversial opinion...
DS9 benefited from the creative interplay as Behr and Rick Berman challenged each other.
I haven't watched the DS9 documentary, but I remember back in the day the feeling you got from the interviews Ira Steven Behr and Ron Moore would give is that as
Voyager came into being, Berman and the Paramount suits felt
Voyager was their flagship
Trek show they micromanaged and it gave DS9 more autonomy.
I think you're right, in that a production is helped by someone that has the power to say "no" when creatives go a little too far. Some of Behr's ideas are great, but some I side-eye at, like the "Benny Russell" ending.
I remember reading one of the big disagreements between Behr, Moore, and Berman was the Dominion War arc that starts season 6. If I recall correctly, Behr and Moore had to fight to get it to be 6 episodes, and wanted it to be longer (e.g., I can't remember if their original intention was for it to be the entire season or not). But Paramount, especially, was not a fan of serialization in the syndication days, since they felt
Star Trek functioned better, especially when trying to sell it to independent TV stations, as a show where people could casually view it with no backstory, and come into an episode without knowing anything except the basic dynamics of what
Star Trek is and enjoy the show.
Also, I believe Berman wanted there to be finality to the Dominion War arc after those episode, similar to how the TNG 2-parters closed off certain story elements, where Behr and Moore had to fight for it to be what it ultimately becomes, which is a significant part of the arc, but only a pivot point in the overall war.