Almost all (if not all) entrepreneurs thrive on the creation process, but not all thrive on the nurturing part once a company reaches a certain level. Sometimes, the creative process just isn't a big enough part of the process anymore when the day-to-day stuff starts to take over a bigger part of a founder's time. Better to leave openly than to stay and not really have your heart in it.

These types of people don't have the DNA to run big companies long-term. But it's always interesting to see where they go next.