You cannot make a P6 conference. You can daydream all you want. The quality of the G5 teams doesn't matter. They are G5 for a reason. You can make up different scenarios and different configurations until the cows come home. None of them will work. It isn't about the quality of the teams. It isn't about fairness. It isn't about rankings.
It's a private club and nobody is wanting to divvy up the cash. There is no way in the world the current P5s are going to wake up one day and say "Let's give up some of our power and money for no reason whatsoever!"
It would take an external authority like the NCAA (LOL) or the govt getting involved to even the playing field. And in that case I thing they would just leave the NCAA.