It takes more than being good at something to operate a successful business. The devil is in the details of all the other parts and pieces of your business, like finding customers to buy your product(s) or service(s), keeping records, eagle-eyeing expenses, managing employees, streamlining operations, understanding how money flows in and out of your business, accounting, and more!
So while you don’t need an M.B.A. to run a business, you do need to have a strong understanding of the functional areas of business so that you can oversee them or hire the right person to manage them for you.