But I would basically differentiate between different film producers, film types (real or animated) and countries. Personally, I watch very different films; German, Japanese, Chinese, Korean, French and don't leave it at the USA alone.
Moreover, this criticism should refer to different parameters of film production: Plot, directors, script, excessive use of CGI effects, camera work, acting performance, etc.
"Back then" technology was different and you didn't have as much leeway in development as you do today.
Miyazaki, for example, in his Ghibli films wants to preserve the time-honored tradition of hand-drawn production, which involves a lot of effort and work, but achieves a beautiful effect, which is why he got into a dispute with his son, who wants to resort to computer animation and modernize the whole thing.
I would look at the whole thing more differentiated and not necessarily put the earlier film production as the ultimate in the film industry and rather put it into perspective with the present.
Nowadays, a lot of garbage is produced that is just supposed to look fancy, but only serves as entertaining entertainment (see "Ready Player One"). However, there's nothing reprehensible about that either. Not every film has to live up to a standard of profundity and artistic excellence. Sometimes shallow entertainment is desirable and good, only it should be criticized appropriately.
There are enough modern-day treasures that shouldn't fail on the premise that movies are invariably bad these days; especially if you move away from the Hollywood bubble and look at movies outside the mainstream.