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.
Maybe I was a little radical in the OP. The fact is most people don't need to agree 100% with what I said for Hollywood to be in trouble. If 50% of movie fans decide that 20% of the movies they'll watch will be free old movies, the demand for paid movies will already fall 10%. If these numbers keep increasing little by little over the years, it's easy to imagine a scenario where half of the movies consumed are public domain. I don't know how much of the total number of books read every year are public domain books, but I would guess it would be at least 25%. I will try to find some research about this.
Other thing is people don't look for historical accuracy and political lessons on movies. The vast majority of them just want entertainment. For each movie made about the holocaust, you will find a dozen generic thriller movies that are very similar to what people have been producing for the last 90 years. So you can find escapism in 1930's Hitchcock classics easily. And you can watch your new stuff later, but your screen time with paid movies would already have been reduced, and Hollywood won't like it.