Don’t underestimate #4. It’s not easy to get people to sign up to a whole new system/site. OF is a known entity. Plus, running an entirely new business (software business) is not easy. Several of the celebrities that have done this are B-listers at best, not always the most informed/managed and good with money. Real A-listers steer clear and don’t want to be associated with that brand.
Business model is everything. A bad operator can have success with a great model/offer. A great operator will still struggle/fail with a bad model/offer.