I've had this theory running around in my head about followups to any series. Every person has a slightly different take on what their favorite part of the show is. For OG Star Trek, maybe you liked the banter between Spock and McCoy. Maybe you liked Kirk's swagger. Maybe you thought Scotty was hot.

If a new production comes along years later and doesn't reproduce the specific elements you like, then you will hate it. The producers might have been ultrafans of the original with good writing chops, a solid cast, and high production values, but if it doesn't have those specific elements for you, then you'll hate it.

Those elements are different for everyone, though. The list of possible elements can be very long, and no new production can possibly check off even a significant fraction of that list. Therefore, any new production is bound to have a long line of haters regardless of its quality on its own merits.

Was Star Trek supposed to be about Kirk, Spock, and McCoy on a ship strutting around the galaxy? TNG changed that. Is it at least supposed to be about strutting around the galaxy? DS9 changed that. Should it at least be about interacting with the alien races we know? Voyager changed that. And so on.

JMS made a Star Trek pitch back in 2004. I like Babylon 5, but I don't think I would have liked his version of Star Trek. The outline focused on elements I didn't care about and just seemed meh to me in general.

This goes for any other long running series, of course.