While kids moving away to campus is part of the problem, the big problem for WT is that colleges and universities try to teach critical thinking skills. As mentioned by several already, WT wants people who know how to read and perform assigned tasks, but they don't want people who know how to think for themselves and question what they are told or read. Consequently, WT wants the sheeples to stay close to the control of the cong and org. And they want them to make money with skills that they might get from limited classes... but not let them be exposed to the type of thinking that might go with a liberal arts degree.
In my experience, the only time that JWs will "think critically," is when they want to get around WT directives. In this case, the GB gives the directive for no schooling beyond the minimum, unless it's a "get your plumbing certification" class at a local college. However, plenty of JWs start thinking about reasons to sidestep. As mentioned in the OP, outside the US they can say, "that only applies to America." Plenty of others around here have pursued degrees saying, "It's a skill that bethel is requesting, and I intend to go to bethel." Others, "I'm pioneering and only a part-time student living with my parents. So that's okay."