The problem is that most non-technical people with "ideas" don't have money, don't have connections, are not amazing at sales (otherwise they would have both money and connections) and don't even know now they are going to acquire customers.

They might think they are good at sales, but if that was really the case then getting enough money to hire someone to build your prototype is not that hard. Freelancers are everywhere, you can judge them by their portfolio, and getting someone to build you a greenfield project at market rates is not really difficult.