The problem is when you've already sold to your entire market (or close 'nuff). How do you keep getting revenue? Upgrades. When everyone's happy, and you don

The problem is when you've already sold to your entire market (or close 'nuff). How do you keep getting revenue? Upgrades. When everyone's happy, and you don't want to rock the boat with improving existing functionality (or if you don't know how), you have to add new features.