[throwaway202212]

By first hand I mean you're the executive paying the bill and understand the motives behind hiring a consulting firm and the incentives such a firm is working under for the client. I'm doubtful most here have that experience (I certainly never did in 20 years of industry before joining a consulting firm). Having McKinsey or BCG walking around your office and telling you what to do is not first hand experience in my opinion.

I'm trying to offer a unique opinion of a software engineer who spent a short time working in this industry. If you're not buying it then no problem.

Personally, I would never invite McKinsey or any of these companies into my own company. But then again I don't run a 100k person company.