Last year we saw Mickey Mouse going public domain and now every year more and more talkie movies are going public domain too. The talkies began in 1928, and I would say they got very close to what we have today in about 1934 or 35.
That means that every year people will have hundreds of “new” releases on public domain, making paying for watching new movies unnecessary. One thing is preferring the new movies when you have to pay both for new and old movies. Another thing is paying for new films when you have hundreds of old movies as good as the new ones (or better) for free.
I don’t know about you, but I could spend the rest of my life watching public domain classics, no problem. For instance, I read a dozen books last year, only two of them were less than a 100 years old.
I would say Hollywood is in a pinch right now, something that will make them miss the days when their biggest enemy was piracy.
Acting techniques improved massively during the XXth century, so stuff that relies on that (basically anything but slapstick Comedy and mindless Action) will feel less believable, which impacts mostly things from the 60s and earlier.
Then there are the Production values: the scenarios in early XXth century films were basically Theatre stages whilst more recent stuff can be incredibly realistic (pay attention to the details in things like clothing and the objects and furniture in indoor scenes in period movies) and Sci-Fi benefited massive from the early XXIst century techniques for physically correct 3D rendering and Mocap techniques so there is a disjunction in perceived realism between even the early Star Wars Movies and something like The Mandalorian.