But the pie has also only stayed the same size (or possibly shrunk) from the perspective of people-chair-hours in big chain theaters. Scorsese himself is an example that a lot of the same filmmaking is still happening, it's just moved to Netflix and other streaming services (and "prestige Cable", which is a branch of streaming services).
It's interesting the forces trying to fight that "real cinema" means people-chair-hours in building labeled a theater, and the obvious fact that the more serious/prestige/independent cinema is increasingly moving directly into people's homes. Netflix versus Cannes, for instance, has just been a fascinating thing to watch, because you've got economic forces versus traditional nostalgia for a cinema that only briefly ever existed as people-chair-hours, and has always been fighting economically for theater time versus whatever "lowest common denominator" fads were current (look at complaints over the decades aimed at Universal's early monster movies, the many decades of cheap musical spectacles, the eras of cheap westerns, etc and so forth).
If you need big events to push people out the comfort of their home theaters and streaming services, of course it is going to be some "lowest common denominator" fad.
(Also, mafia/gangster films were another one of those cheap film fads, and Scorsese and others "elevated it", but that was once considered a genre like we consider superhero films today that maybe didn't qualify as true "cinema". What debate that is old is new again.)