A new business should offer a solution to a problem. It can be a local problem, a problem specific to a subculture or hobby, a tech problem, a big societal problem, etc. So if you’re really looking to start at ZERO then start asking what are problems that you’ve encountered in some space, where no one has offered a solution. And if you can conceive a cost-effective, logistically sustainable solution to that problem then you have your business model.