¿What process use the founders to know about if market needs?

The most problem to has the founders is market not need this products or services, if the founders can know about that information, they wouldn´t waste resources and time. Part of the work is about validate the product, market, price, etc to reach the product market fit. The pain to close a startup is innecesary if we got the tools to measure the idea impact in the market. We have methodologies to make a minimum viable product, prototype´s, etc, but we dont have a integrate tool to solve this problem, it's curious... Currently ¿What process or tools use the founders to know about if market needs?