The reality is - more nuanced. Certainly there are many who consider both GS and McKinsey to be very bad things indeed, and not in any way a professional niche that high quality graduates should aspire to.
Perhaps there may be more to "intrinsic quality" than an obsessive work ethic and social connections?
My experience has been the opposite to yours. People who don't have technical degrees but have been trained to consider themselves experts in business management generally overestimate their own skills, and vastly underestimate the skills and insights of those (nominally) "under" them.