Well, that's an interesting point you raise. I see it as critics using to have some "skin in the game". They used to be either recognized artists themselves or later the patrons, or someone that was paid by the patrons to critic works and find the best artists to work for the patrons (I see that part a bit like the people that today search for young talents for big football (i.e. soccer) teams).
With the democratization of art that followed the subsidizing with public money of artists an all new class of people was born. One that didn't really have that same "skin in the game" but had at their disposal money that wasn't theirs to distribute as they saw fit.
I believe that gave rise to situations like you mention. Yes, there are a lot of excellent movies that were destroying by early critics (not saying that didn't happen before, I'm very well aware of great music compositions being ruined because some monarch didn't like the opening concert). The thing is, why do we let (and keep letting) those critics to be some kind of gate keepers of art?
Here is some interesting read about the history of art critics: https://www.artrewards.net/editorial/the-evolution-of-art-cr...