Maybe it’s easier to define by looking at what is unsustainable.
For example, if current trends continue there will be a formal separation of P5/G5. The NCAA will create a new subdivision and the 40% or so of the P5 level schools will represent what’s now the FBS as Division 1 P5 or whatever name is chosen.
If BYU is not in that P5 group when that happens, it will be the most significant program excluded. And my thought is that independence will not be enough to bridge the gap between P5 and G5.
Getting locked out after the division occurs will doom BYU football. The BOT may try to carry on a few years but after a few years of running in the red they would very likely pull the plug on all athletics as they have done with Ricks and BYU-Hawaii.
So for me, when you boil it down, independence is either sustainable (meaning it gets BYU into the P5 club somehow), or it isn’t (meaning BYU gets relegated to the second tier of college football, starves financially, and dies a slow death).
I dislike independence for multiple reasons, but I have to admit it probably gives BYU the best chance to scratch and claw its way into the P5 club.
The next five years are more critical than any other in BYU’s history, in my opinion. There’s never been a more critical time to win.