To transfer accountability for risky decisions?

I think it's a common misconception that management consultants are hired to provide advice or add value. If you look at who actually does the work (sleepy, recent college grads with zero work experience and no understanding of the target industry), how could consultants add value? Do you really think a CEO with 20 years of experience in an industry needs/wants a PowerPoint about strategy?

The reason they're hired is that decision-makers at firms want to take risk, but they don't want to be fired if it blows up in their face.

If I'm a CEO and I hire McKinsey to recommend to me the thing I already wanted to do, then I can take credit if it works, or I can cover my ass if it fails and say, "McKinsey's Harvard-trained consultants told me to do this."

Other firms, like Accenture, actually do some implementation of projects, which means they're also a temporary staffing solution in some cases.

zero documentation, you have to reverse engineer all the circuits, soc's, and everything up the stack from there. Obsolecence by obscurity.