As John Oliver mentioned, the consultants are not supposed to learn from their customers but from other consultants.

If you got expensive hammers, the solution is to treat a problem like nails.

If the consultant told the company the managers that they were idiots, they would have been kicked out. It is much better to get the contract and milk the idiots. At this point, they are less doctors and more shamans with expensive placebos. If the patient survives, you could claim success. If the patient dies, nobody is going to be around to get a refund.

Survivors get to rewrite history.