The same goes for Paul. There he was with position and presumably wealth in his community. All of a sudden he makes a 90 degree turn, in a way that in secular terms can only be described as an extremely poor career move. Once again, it seems sensible to believe his own account even if it does sound implausible.
This may be off topic a bit, so it may be best to start a new thread on Paul. However, I think it's not entirely necessary that Paul had position and power. From what I've read, he was a low level functionary who had no opportunity for upward mobility. It seems plausible to me that Paul was an ambitious man, and couldn't rise any higher in the Jewish community being from the proverbial sticks.
As for his "bad career move." He took a small Jewish sect, and saw an opportunity to become a high placed leader in that sect and affect it's evolution. And now, 2000 years later, we're still talking about him. I would consider that to be a very good career move.