It's a bitter thing but, ultimately, movies, especially the 'event' movies that studios depend on to keep up their cash flow, are expensive. Understandably, the studios are only willing to risk that sort of money on what their marketing guys tell them is a sure thing. The big problem is that franchise movies and sequels are not a sure thing in quality terms. Eventually, cookie-cutter repetition and the loss of all the originality that created the fan-base in the first place alienates fans and poisons the well, making the brand toxic.
The sad fact is that Lucas would never got Star Wars funded today. Too many risks: a largely unknown cast, an original screenplay and a genre that had previously been regarded as a niche outside of TV.
Although I love MCU, I really think that the wrong lessons have been learned from its success to date. We want fun and positive films, not adaptations of debatable quality of existing franchises from other media! Indeed, by the looks of things, even MCU, the standard-bearer, seems at risk of being drowned by schedule-fillers that will not contribute to the grand arc that promised to make it a modern model of how to make a multi-part franchise great.
