Simply because they thought they didn't have to work. Maybe,they thought that they didn't have to invest any amount of time or money. Or, maybe they thought it was a get-rick-quick business.
Then again, many people sign up for different home-based businesses and then do nothing with it. They may become overwhelmed with all the information that is offered on the website, and, all this information may have just confused them so they gave up. Sometimes all the information just scares them off.