that is Indy is because it is one of the only teams outside of the P5 that can actually pull it off. IMO, if Boise could get the deals BYU gets, they'd dump the MWC in a heartbeat.
As an Indy, BYU has a schedule that almost approximates a P5 school, considerably better than as a member of the MWC. I want BYU to play big time football. This, currently, is the best way for BYU to get that done.
As an indy BYU has become a de facto P5 team, from the POV of the P5 itself. As a G5, we are second tier.
As an Indy, BYU has plausible deniability that they aren't 'big time' to recruits. As a G5 that argument can't be made and we might as well gift wrap the recruits we are competing for to Utah and Stanford.
IMO, if BYU could get into a P5 conference they'd be crazy not to. If they can't, they'd be crazy to join a G5 conference. College football is moving inexorably to the 'haves' and the 'have nots'. BYU must, at all costs, avoid becoming a clear cut 'have not' by joining a G5.