P5 IS already autonomous....P5 is a shortcut name...but the NCAA designates them as "autonomy conferences"....In terms of football, they are autonomous. They can make their own rules.
The conferences that comprise the Power Five are designated by the NCAA, individually by name, as "autonomy conferences". Section 5.3.2.1 of the NCAA Constitution grants such conferences autonomy "to permit the use of resources to advance the legitimate educational or athletics-related needs of student-athletes and for legislative changes that will otherwise enhance student-athlete well-being". Eleven areas of autonomy are listed, including promotional activities unrelated to athletics participation, pre-enrollment expenses and support, and financial aid.[3]
I think that football, already autonomous, is as far as the P5's want to go....that's all.