When Snyder first came, Kansas State's football program was on life support and it had no tradition. That is no longer the case. With the success Kansas State had since the early nineties, it's not like you are starting all over with Prince. Kansas State now has a football tradition, so even if Prince doesn't work out, the next coach can build off of it. Snyder made KSU a winner, so even if you have bad seasons, you won't fall back into the pre-1990's, IMO.
Nebraska wasn't exactly a powerhouse before Devaney. It wasn't the end of the world with Solich either.