Like Bama or Ohio State or Clemson then most. If it means being a P5 school then over half.
If it means having a certain number of scholarships available then whichever ones don’t meet that threshold. If it means competing at a certain level then all those who don’t meet that level of competition.

I imagine if there were a limit set on how many total stars were allowed per school per recruiting class then we’d get more evenly distributed competitive teams. But that is not how the system is set up. If 25 5-star recruits chose to go to Bama each year and it fit what positions Bama needed then Bama would get 25 5-star recruits each year. By the nature of this system it means the bottom of the totem pole (the UConn’s and UMass’s) are no where near the level of Bama and Ohio St. I don’t believe that means they shouldn’t be FBS.
So my answer is 0 because a line has to be drawn somewhere.