I've no idea either - tbh it's quite possible that it ends up being the blind leading the blind, but if you're paying hefty fees it feels like you're actually doing something.

Related note - The Armando Iannucci Shows (by "Veep" creator, about 10 years beforehand) tackled Management Consultants very well: https://www.youtube.com/watch?v=MSJggp-mbiA&t=0m58s