Hmmm...lots of reasons.

A better opportunity presented itself.
Someone in his family got ill and he wanted to spend time/take care of them.
Needed to change locations due to health reasons.
Didn't like the school system.
Was arrested for knocking over a liquor store.
Fired due to domestic violence.
Won the lottery.
Got tired of having to deal with people like...well...difficult people.

I could go on and on, but none of the reasons above meet the nefarious requirements you're trying to insinuate. I'm focusing on who's the CEO and on the board now. I don't share your opinion that there should be a shakeup right now. I'm not totally happy, but I'm not totally unhappy either.

But I'm bowing out of this discussion. Have at it.