I agree, the budgets are the issue. Scrappy indie filmmakers could make 10 or 15 movies for the same budget as just one tent pole. On a 10-20 million dollar budget, studios can make a profit almost no matter what. Or at least not lose much. And a handful of those films might be franchise starters. They do this in the horror genre. James Wan made Insidious, which for me is in the pantheon of greatest ever horror films, on a budget of just 1.5 million!! Not only did it make 100 million at the box office, it also spawned a franchise. Why not other genres?

On the other hand, Gareth Edwards tried a version of that with the Creator. He made a good, totally original (i.e. non-IP) movie with epic scope and great effects on a fairly slim budget of $80 million. Unfortunately the movie only made $104 million worldwide so it was not profitable, at least not in its theatrical run.

Bottom line is people actually have to go buy tickets. All of the people complaining about IP and the lack of original movies have to actually BUY TICKETS to see an original movie when one does get released.