It's a relatively recent change, too. Transition from "the executives and managers mostly came up through 10-25 years of doing 'lower' jobs in the company, and very much know how the business actually works" to "we hire MBAs to those roles directly" was throughout the '70s-'90s.

Finance and business grads have really taken over the economy, not just through technocratic "here's how to do stuff" advice but by personally taking all the reigns of power. They're even hard at work taking over medicine and pushing doctors out of the work-social upper-middle-class. Already did it with professors. Lawyers seem safe, so far.