While I agree with you that starting with the idea and then trying to find a problem is backwards, starting with the problem is fraught with issues too. Unless

While I agree with you that starting with the idea and then trying to find a problem is backwards, starting with the problem is fraught with issues too. Unless you are working in the industry you want to target it is unlikely that your problems are either common or serious enough to make enough people fork out money to make a viable business. Identifying good business problems to solve with technology is very, very hard. Almost all the ones you can identify are too small, too trivial, or illusory.