In aggregate and over the long term (~100 years or so in the case of consulting), most services find a fair market value. If McK is a ~$15B company running at ~30-40% margins, it is likely delivering some value to someone who is willing to pay for it. That value may be overstated to people not paying for it, or they may not understand the value because they are not faced with the same challenges as the typical McK customer.
...and that's ok, they are not the intended market.