Don't see the point in blaming him.
One of the following:
- It is his own real reason, and he's entitled to do whatever he likes with his business (unlikely)
- He received pressure, but obviously he will not say it publicly (possible)
- He has read the writing on the wall and decided to leave and enjoy the profits before they put him in jail (likely)
At the end of the day we can only speculate as to the reasons, some people will be unhappy but he is free to do whatever he wants.
He likely has more than enough money to last him the rest of his life anyway so good on him for deciding to call it quits I say.