Unless their football team just continually sucked - and by "sucked" I mean mid-80s sucked - they'd eventually grow to more or less equal BYU, because they both share the same local market, and neither has a huge inherent advantage.
Some think the Pac-12 will give them that advantage, but it's far too early to say.
The point is, nobody at BYU could've stopped it from happening. A season or two might make a difference to some band wagoners, but only temporarily.