Julia' s point is well made. One becomes so indoctrinated that life outside the ORG is "too scary" and so they stay in. In essence, it becomes their culture just as much as the Amish or Yassidic Jew for that matter.
Most, however, are not that way. Most of the kids I see in the hall are not really "witnesses" in the same way I was a "witness" as a young man. They go to clubs, party, drink way more than I ever did at that age, and do absolutely nothing to "promote Kingdom interests." Bethel service is rarely mentioned among the young men. They are interested in what every other young person wants....independence.
I woudl venture to say that when most fly the coop of their parent's supervision, they will rarely if ever be seen at some "theocratic" activity except for assemblies to scope out chicks or get togethers to scope out chicks.