It's been that way for a loooong time.
Movies became so expensive to produce that studios can't finance them themselves.
So they turned to the banks.
Banks are by nature risk averse.
So a production company has to submit an application to their bank's movie financing department like you would when applying for a home loan.
The bank decides whether to finance the movie based on the information submitted: Script, subject matter, director, which stars have committed to the project, etc.
Now if you imagine, people from the banking industry are not artists and creatives and visionaries. They just look at raw investment potential, i.e. Is this proposed production going to pay off the loan with interest?
If there's any risk, e.g. this has never been done before, or there's no recognizable franchise branding, or if something could be controversial in a meaningful way, the bank won't approve the production loan.
So sequels, brand name franchises, with writing committees, are easier to get approvals from the banks, therefore are more likely to make it into production.
That's why Hollywood doesn't make daring, experimental, and controversial movies much anymore.