I do think that even if it is not a control issue, that the feeling of superiority JWs feel keeps them in the organization. Because so many haven't gone to college, don't have careers, in the real world they would be "nothing," but in the org they are told that they have real knowledge that even those who have been to the seminary don't. My mother is one of the superior JWs. She feels that she is better than worldly people, and most JWs because she really knows the bible (NWT). In reality however, she can barely keep a roof over her head. In all other aspects of life she is a perpetual screw-up. The KH is the only place where she has self-worth.
As far as some people staying so they can control others, I guess that could be so, for males. Even if a man has a crappy job at the bottom of the totem pole, he can still have control over the lives of others through being an elder. I think TPTB at the WT take those things into account when they discourage school and careers. If you keep people in a lowly position in life, and elevate them in the congregation, they will hold fiercely to it because they have nothing else going on in life.
Oh well, those are just my thoughts.