A book called "Lords of Strategy" tracks the consulting "apple" thing. It is a good read. Sorry for duplications. I think overall management consulting is a world ready to be distrupted (if not already). Regurgitation sold as overpriced thoughtware
It’s the same reason the same big 4-5 federal contractors win most of the work. The sunk cost in needed bureaucracy is large, it’s hard for a small player to compete.
The root issue is big co procurement has taken accountability away from the people who actually use and understand the services. So in my company’s case it’s common to start a relationship with a counterpart at a firm very willing to invest in our services. Sadly the procurement bureaucracy really gets in the way of progress making everything more expensive for both sides. If you’re Accenture and McKinsey you just (unethically in my opinion) sink the cost but then milk the relationship for all it’s worth.