While it is expected that the quantity of good movies will fluctuate from year to year, every year has a good set of movies. Therefore, I believe that it is not that a particular era of movies was better than the current state of things, but that we may just like movies from a particular era and can’t identify with what is current.
To double down on some of the things listed here, Barbie was really good, Infinity Pool was amazing, I cannot wait to see Poor Things and The Boy and The Heron, Saltburn was excellent, Nimona was just AAAAAAAH!!!, I thought Air was well done and pretty entertaining, and so was Tetris.
We should always keep in mind that when we look back at previous years, we tend to only list the films (or anything else) that made the biggest impact and conclude that those years were excellent compared to whatever is happening right now, and we do not take into account that the list is really small compared to the amount of shit films (or anything else) that was released. Someone in 1999 probably looked at the really short list the most important films 1976, compared to what was fresh in their memory in 1999, and concluded that there aren’t any good released in '99…
To give a bit of perspective on my comment, I am almost 50, didn’t care about comics as a kid so I have no investment in Marvel this or that, or anything that fuels people’s obsessions, so I think I fit the demographic that would could be saying “movies suck now”.