I simply cannot determine if you are trolling or not. Seriously.
Let's say you decided to open your own business and your business was selling cupcakes. What happens if you don't have any customers?
Yes, that's right. You go bankrupt; you can't pay your bills; you could lose your house, your job, the business and probably the underwear you're sitting in while you post this type of question.
If you sell something - books, cupcakes, clothing, gyros, etc. - you have to sell them to someone which is the Customer. No Customers equals no money. Hope that helps.