Hollywood struggles to think of anything that isn’t a reboot or a sequel so they’re digging up all these older movies to mine ideas from. It very rarely works out well.
Actually, I think the real issue is more how advances in technology have affected them. You have to bear in mind, Hollywood has done sequels for ages. Dirty Harry, Rambo, Rocky, a good deal of older horror franchises… all with their fair share of sequels. It didn’t get overwhelming though until we moved into a situation where easy file sharing became a possibility, and electronic devices suddenly began to allow instant feedback on movies and films. You suddenly have a situation where they start losing on ticket sales in theaters (one of the big ways they earn money on the films they produce) at the same time bad movies (which use to take a while for people to learn how bad they were and subsequently were good for earning a little extra money) can no longer be counted on for a quick, easy buck. So they’re forced into a situation where they’re scared to fund anything the viewing public doesn’t already like, leading to fewer original pieces and more shared universes, multitudes of franchise films, and so on.
Of course the smart thing to do would be for them to adapt to the technology, since piracy obviously isn’t going away (and I’m certainly not going to fight people who don’t want to pay $20 and up for 2 hours in a dark, crowded room with people coughing and making noise) and find alternative ways to make interesting new films, but change is one of those things takes time and consideration, not things that have ever really been studio executive’s strong suits.