Donahue shot his wad at Cornell by building a team for one big run. It worked as he won 3 Ivy titles with that group and eventually rode about 7 seniors (including a 7 foot transfer center) deep into the tournament. Everyone knew he was leaving as there was not much talent, and even less experience, coming back. The only returnee that had played meaningful minutes was a guard, Wrobelewski.
Unfortunately for ambitious coaches they forget one thing - the grateful school that they just lead to unprecedented success will probably give them 4-6 more years to get the program turned back around while the disastrous "upgrade" position (if BCU can even be considered an upgrade) they jump at instead feels no such obligation and expects to see results far sooner. Donahue probably gets one more year if Flipper stays, but he could be out sooner if a new AD comes in. It may depend on how many contracts the wounded eagles can afford to buy out.