> The other thing management consultants do is industrial espionage -- they go into a company to learn how it work, and then advise other companies on how "industry leaders" operate.

This one doesn't get mentioned enough, I think. They'll happily sell you an outline of what you need to do to be in line with "industry best practices", where those practices are all the things your competitors are doing better than you (and guess what they'll sell those companies if they spot anything you're doing better than they are? Where do you think they learned about those "best practices" in the first place?).

It's basically a kind of weird, expensive, inefficient, unofficial business process collaborative R&D program.