The NCAA has never had any real power. It is up to the members to follow their own rules. They can still have a role to establish game procedures e.g. overtime, allowed blocks, targeting definition and penalties etc. They still set the number of allowed scholarships, minimum qualifiers etc. It is supposed to be overseen by the presidents of the member colleges but it has become run by the athletic departments for the most part. It would not surprise me to see the P5 conferences split off to form their own association.