this idea that snyder kept coaching ONLY because he wanted to hang on until there was an AD that would hire Sean, is insane and not based in reality. did he want Sean to be head coach? sure, he said as much. but there is no evidence he went to any meaningful lengths to make sure that was going to happen.
snyder is a stubborn, weird, old man that knows coaching and coaching only, and wanted to keep doing it as long as he could. it is as simple as that. he held on too long and became ineffective in his last few years, and for what it's worth i was ready to see him leave.