and these P5 teams determine that they don't want to play anyone outside of their exclusive club, then yes, absolutely independence has no benefit. BYU will be relegated to the 2nd tier division and need to join a conference.
Independence has never been a permanent plan. The changing landscape of college football is going to dictate BYU's position. Either a big conference is going to invite them, or this breakaway by the P5's is going to happen and leave BYU in the dust.
I could be wrong. Maybe there are antitrust issues that the G5's could leverage to keep it from happening. But if there are not, I am sure we see it happen by 2025.