Speaking of McKinsey...
My current company just finished a year of consulting with McKinsey. They basically sucked millions of dollars out of us for no perceived benefit.
Their basic MO as far as I can tell is not to try change how the business is run and fix the basic issues that those of us at the bottom can clearly see. They can't do that because they don't know the business we are in. What they therefore do is simply try to have the business do the same exact inefficient things, but cheaper. Usually by fleecing suppliers and replacing employees with cheaper ones in low cost countries. Somehow executives always avoid this fate...
Sadly most companies and government appear to be run exactly the same way - the incompetence always rises to the top and when they eventually get fired they just move on to the next large company. (it has to be large as they'll get found out quickly in a small company!).
For those interested (and yes this is a plug for him), my colleague wrote a novella about us:
It's a short read, but basically describes every public company these days , and most local governments too!
Anon for obvious reasons.