I agree with everything that's been said here. But it's hard to imagine anything other than an directly proportional relationship beween college eduation and corresponding earning power, and money available to donate to the WT.
Even the people that run the Tower have to know this. By championing the briefest (and least) possible eduaction for JWs, the WT is effectively shooting itself in the foot.
Unless of course, they have performed a cost-benefit analysis, and determined that it's better to have broke JWs who can't reason, rather than better-off JWs who might reason and leave.