BYU football isn't going anywhere. And that fan base is only going to continue to expand. When your fandom is tied to something many of us feel strongly about - namely, the Church, then a few mediocre seasons isn't going to scare us off. And, I'm not sure anyone has noticed, but Utah County is not exactly shrinking in population. It's exploding. Fan support will be there.
And there are other big advantages. We already have P5-like facilities. We don't have what the elites have, but we match most P5s in this area. We carry no debt. That helps us stretch the money we go have farther, and also eliminates a big risk that many programs face - an inability to actually pay the bills. BYU won't ever have that problem.
Anyway, these thoughts that BYU football is just years away from complete collapse are ludicrous.