Bill Gates is a brilliant computer programmer, but he doesn’t spend any time writing code these days. Don’t ask Ben & Jerry to make you a sundae, or Mrs. Field to bake you some cookies. Thomas Edison died a wealthy man not so much because of his revolutionary inventions, but because in the latter stage of his life he got out of the laboratory and went into the business of marketing his inventions. Giant electric utilities now known as ComEd and Con Ed are among the businesses that arose from original Edison ventures.
The lessons are everywhere you care to look. It takes more than mastery of a craft to run a successful business selling the output of that craft: You need to tend to the business of running a business.