At the same time, the world of Star Wars itself, as an example, is now available in a way that it wasn’t before, so filmmakers inspired by it can make their own entry in the franchise, and, as Rian Johnson has recently proven, there’s still plenty of room to be creative, even from within an existing franchise.
It’s certainly true that we’re seeing less of those sorts of stories.
It’s a famous story that George Lucas created Star Wars, in part, because he wasn’t able to get the rights to make a Flash Gordon movie, so instead, he made his own thing inspired by that idea.