My response:What differentiates a great management consultant from a good management consultant?
A good consultant solves a client's problem.
A great consultant gives the right tools, techniques and perspectives that allows clients to understand & solve their own problems.
The first guy ensures that he gets a client (and an income stream) for life i.e. someone who calls him back whenever there's a similar problem.
The second one doesn't shy away from making himself redundant if it's in the client's long-term interest.