What a lot of people don't realize is that being a monk in Buddhism isn't like being a priest or nun or going into a yeshiva... all Buddhist males have to spend at least 2 years as a monk before becoming an adult, and many adults go in and out of monkeries. It isn't retiring from the world necessarily, although there are plenty of monks who are lifelong monks.

It's like Europeans having to do 2 years in the military - it doesn't mean they are career soldiers.