Almost every public company has a CFO and/or COO that has an MBA. It's not an 'in spite of;' financials get complicated as do business operations and those two things are what an MBA is for, other than networking.

Also, I know a lot of entrepreneurial people that do not do very well when the company gets beyond a certain size. They can't operate within a system of greater restriction and don't want to follow best practices for employees. Managers are often not good builders and builders aren't always good managers.