I expect ups and downs for BYU. But BYU is probably in the best position of any program in the nation for sustained LaVell-like success.
They are in a conference where they have far and away the largest fan base, the largest recruiting base, and (presumably) the most money. I don't consider them the 'big fish in the little pond' because I know the other good programs like TCU, Utah, CSU, and UNM will have 'up-years' where they might run through the conference. But I do think BYU should be competitive in conference year in and year out.
I guess I think that in conference, at least, BYU should cycle between 1st place and 3rd place, not between 1st place and last place.
Crowton did happen, however, disproving my theory to some extent.