Consider Utah - under McBride they'd become a solid G5/mid-major team. Not great, but they were consistently one of the better teams in conference, and won more than they lost. Respectable, but not impressive.

And then they hired Urban Meyer. And he transformed Utah, kicking off the process that got them a P5 invite and has them a near-constant in the Top 25. But before that he had exactly two seasons as a HC at a small school in a mediocre conference in the middle of nowhere. Before that he hadn't even had a coordinator role. Sure he'd looked good in those two seasons, but it was largely running (what was then considered to be) a gimmick offense and with the previous regime's recruits.

So he was a risky hire in some ways; Utah could have easily found a coach who was more likely to keep them playing at a respectable, not great, level. Urban Meyer was a big swing, and ended up being a Home Run for the school. But it meant they needed to hire him before it was totally clear that he was a great HC or not.

And that's what every team wants - the big swing, the home run, not the "pretty good" coach. But they are all trying to unearth it first which means they have to be REALLY aggressive trying to find it and jump on anyone or anything that shows some potential. If they don't, some other school will and they'll miss out.

Similarly, Crowton, Mendenhall, Sitake were all plucked from relative obscurity.

And this doesn't even get into how difficult it is to evaluate at lesser roles where there's generally even more unknown. Plus you have to consider recruiting ability, how much a school pays (BYU has a poor rep in this regard) and competition from other schools or likelihood your guy will be quickly poached.