The only times I've seen anything remotely like that work, it's a situation like this: Two engineers work together at company A, become friends and gain experie

The only times I've seen anything remotely like that work, it's a situation like this: Two engineers work together at company A, become friends and gain experience in the domain. Both move on, progress in their careers and work other companies in the same domain. They meet for coffee and person 1 says: "hey remember that problem we had at A? I see it again at B", person 2: "me too and I've been working on a side project to fix it, you should totally buy the solution from me". And voilà. Could a kid right out of school build the same thing? Sure. Would it have ever succeeded? No. They lack the domain experience and the social connections to do it.