Think of it in terms of open source projects, where the projects that you might be interested have only a few people working on them - but in the context of issues that affect folk completely outside of tech who don't have disposable income like those you'd see on HN or similar.
I seriously recommend that you check out a local "open data civics" group, or something similar in your area. You'll find that they're generally filled with junior programmers - but what they need are senior level programmers who can take charge of problems that junior programmers otherwise can't take charge of. Be that person.
FWIW, personally everything that I learn is entirely aimed towards helping the general public (at a distance), at the expense of my own salary. The work has been very rewarding. That said, it would be great if others would take the plunge that I have.