Earlier quoted context omitted.
If no one will pay for the solution, the problem might not be that important.
While this is true in broad strokes, I think money fails to capture non quantifiable quality of life improvements. Hacker culture being close to the users could solve them, but being driven by money would definitely hinder that development
But in most cases you don't see quality of life improvements unless you also get users.
In other words building it is not enough. Lives need to use it to be improved.
Monetizing an app forces you to concentrate on articulating that value. It frees up resources (ie money) to spend on spreading the word. It offers you feedback on whether this is a meaningful use of your time or not.
Dont get me wrong. An app can add value to a single person. You can give it away for free. There's nothing wrong with that.