One doesn't need to be a consultant to realize how people respond to problems (other than solving them).

But it helps. Perhaps. Maybe even more so if you (=consultant) leave with just the recommendations, without actually implementing them. Which is what most of the Big 4 consulting companies do.

(Guilty, to be honest. And that's why (partly) I gave up mgmt consulting)

But it helps to understand where people are coming from to realize why the problems exist in the first place.