Consultants are also part of the problem.

I did a Master's degree that shared half its classes with the MBA, and we had some case studies where a consultant was the hero by literally tearing down a wall between sales and operations (the small company had communication and "empathy" issues).

I always end up linking to this summary of Chapter 12 of Peopleware:

http://javatroopers.com/Peopleware.html#Chapter_12