That's interesting. I'm curious to know how the internal sponsor of the project sold it internally. It generally takes a lot of motivation to convince your superior (and finance team) to pay the millions McKinsey would charge per week.

At the micro level, I would agree that in some cases there was a tendency of some to make things more complex than necessary. The implicit intent here was generally to demonstrate some type of credential to lay people.

That being said, at least in my personal experience, most of the actual recommendations were backed by as much data as possible. In the projects I worked on, I don't think a single slide went by without hours of debate and critique by the partners. It was a given that any recommendation should be supported by data.

That being said, there are also lots of cases where there is no right/wrong answer - especially given the timeframe (typically 4-8 weeks). Companies basically pay consultants to come in, analyse as much data as feasible and just make some type of informed decision. In most cases the company is either unwilling to make that decision themselves or does not have the ability to do so (i.e. organisation is too complex to tackle this problem within so just get an outsider to cut across the company and get it sorted as best as possible).