You missed their primary purpose: To provide cover for whatever half-assed idea an exec came up with. If the CEO of my automobile company wakes up one morning with the zany idea to cut costs by only including 3 wheels with the purchase of a car, if he just goes ahead and does it, the investors will call for his head when customers stop buying our cars and instead purchase our four-wheeled compeitors. But if our CEO hires Deloitte, they'll make a bunch of reports and excel sheets that show why 3 wheels are the best idea ever. If he wanted to add an extra wheel, there'd be a bunch of reports on the superiority of 5 tires. If he decides to switch back, hire the consultants, they'll dutifully report on how 4 tires was the right amount all along. It's all just an accountability shell game.