Billy Donovan isn't leaving the NBA for a while. He had passed up multiple opportunities and waited until the timing was perfect to make the leap. He's not giving up that quickly.
I still think it's a pipe dream, but I'm not ready to dismiss it out of hand.
There are a couple of reasons Donovan might want to go back to college...
1. Not all college coaches adapt to the NBA, Pitinio and Calipari are examples. The headaches/egos you have to manage in the nba are worlds larger than in college.
2. He might be frustrated with having to compete with "super teams." The nba is set up so that these super teams aren't going away anytime soon. Add in that OKC is a small market team in "flyover" country, and he might look at it and say "I'm never going to compete in this league" and want to go back to college where a coach can have MUCH more control over the type of team he puts on the court. Yes he has Russ Westbrook, but he'll never be able to surround him with the kind of players to compete with the Golden States or Cavs of the world. And before you say it, I know Cleveland is a small market. But they have an owner willing to spend to compete. I don't think that's the case in OKC.
3. $$$. tOSU is one of a handful of jobs that might have the financial resources to toss a pile of money at a coach to come and turn around the program. Basketball will always play second fiddle to football in Columbus, but it's still a revenue sport, and if tOSU is serious about luring a top tiered coach to Columbus, they're gonna have to spend. And they have the cash to do it.
4. Some say tOSU might not be that attractive to big time coaches because it's a football school. That's certainly true in my mind, however, Donovan was already successful once at a football school and I don't think it's as big a negative for him as it might be for others.
Now, do I think Donovan would end up here? No I do not. I would put it at an extreme longshot. But there's enough reasoning, in my mind, to at least see it as a possibility, and if Gene Smith is serious about this coaching search, he has to at least try to land a whale. And Donovan would certainly be that.