The difference to an AD is that if you make an unconventional hire you are going to get more criticism if it doesn’t work, especially in football or men’s basketball. Obviously any hire that doesn’t work will result in criticism, but it’s magnified if you are going out on a limb. For example, PJ and Motzko were pretty conventional. Good resumes at lower tier programs that they had punching above their weight class — giving them a shot at a B1G program was logical. Hiring someone like that (in this case, say Craig Smith) won’t result in the same blowback if it doesn’t work out as hiring someone with a less qualified resume (like a Ben Johnson) if that doesn’t work.
Plus IMO the fan base will have less patience with an unconventional hire. If Craig Smith wins 35% of his B1G games in his first two years it’s easy for people to rationalize it and say “well, he knows what it takes to win his conference and get teams to the NCAA tournament, so I’m still all in”. Whereas if a coach has never accomplished those things it’s easy to look at a 35% B1G win % after two years and say “nope, this was a mistake and there is no reason to believe this guy can get it done because he’s never done it before”. And then you are losing fans and $$.
I’m not saying any of that is right or wrong, but I’m saying that’s reality.