It's widely-acknowledged that many research professors bring a weak grasp of reality to their subject. This so-called "ivory tower" problem usually means that their research is irrelevant to the outside world, but sometimes that research is dangerous -- as we have found with financial theory recently.
One way to reduce this problem is by requiring some work experience in the outside world. Such a minimum, say 4 years, would not fix all problems, but it would change the way that most PhDs see the world. I suggest that this gap be maintained at the leading edge, i.e., 4 years after a bachelors or masters degree before a student would be allowed to matriculate to a PhD program. Besides the obvious -- it's easier to monitor the leading edge than the trailing edge -- this requirement is also useful as a means of bringing more real-world experience into the classroom. Students with experience would be able to challenge teaching that was poorly-framed wrt the outside world.
Bottom Line: The academe is useful (even necessary), and its use depends on its contribution to the outside. Increase the intensity of academe-lay interaction and make both better off.