No they haven't? An app can sell a customer access to their app outside the App Store, give them an account that they can use to access full functionality, direct them to the App Store to download the app, and Apple doesn't take anything. Apple gets a cut when they facilitate the sale, which they absolutely do when a customer is directed to the app in the App Store and then can buy the app with a single tap (knowing it has undergone some degree of vetting and that they can get a refund if they're not happy). If you don't think that is providing immense value, then just consider the difficulty of selling software outside of the App Store. To an approximation, it basically doesn't happen except with B2B SaaS (which notoriously requires a very expensive sales and marketing function).