Well, then you get into the whole territory of "new stuff sucks, only the old stuff is good." Now that the Prequels are twenty years old, they can be looked back upon fondly despite being bashed back when they were new. Star Trek follows a similar pattern with Voyager and Enterprise being hated by fans back when they were airing, but nowadays, they beloved classics. Doctor Who fandom actually incorporates this as part of the process, with it being stated when a new episode airs it will be judged to be crap. Then, five years later the episode is to be rewatched and reassessed as a misunderstood gem and much better than the crap which is currently airing.
I've always thought that the prequel reevaluation was almost as weird as people claiming that kids at the time loved them. I saw Episode 1 when it debuted in theaters, and I was 8 1/2 years old (in may 1999) and it certainly didn't become a childhood favorite, and has not grown on me since then (I was also never a fan of Jar Jar even as a kid, regardless of the weird propaganda Lucasfilm people still try to spread about the character being beloved by children). Episode II, which I also saw on release (when I was 11 1/2 years old), might be the first movie I saw in theaters and actively disliked even as a dumb kid, and I still think its bad. Episode III was also watched on release, and I hold the same opinion today as when I first saw it, that its just ok, but easily the best prequel.
Now, the Clone Wars cartoon did a lot to help the prequel era, I legitimately care about Anakin Skywalker solely based on that cartoon. But the Clone wars cartoon was (generally) so much better then the prequel movies that it doesn't really raise up my opinion on Episodes 1-3, it more just makes me like/tolerate the prequel era overall.
Also, Voyager and Enterprise are not beloved classics by basically anyone that I've ever seen talk about them, and I say that as someone who probably likes both shows more then most people (for example, I think that Enterprise Season 3 legitimately did the "Season long arc" thing better then Discovery or Picard, and I do think that Voyager had a few all time classic episodes, along with the Doctor being one of my favorite Trek characters). As for Doctor Who, I doubt crap like Kill the Moon or In the Forest of the Night are going to get "reevaluated", and thats just a small example.
I don't think reevaluation is as wide spread as people claim. A lot of stuff that was bad when it came out is still terrible, and probably even worse in hindsight. You might appreciate some elements more, but outside of small groups online a lot of stuff gets shit on for good reason, and stays in the metaphorical trash.