Betchya they sell more than you think!
Keep in mind Happs isn't in business to supply individuals. They do, but they make most of their money on big orders to companies. Those little trackballs are meant for manufacturers of kiosks, such as internet access kiosks, cyber cafes, and other PC-based kiosk displays where you need some sort of mouse control, but can't have a mouse due to the public's tendency to be stupid and steal/break such things.