I'm from Romania, Europe. Don't know what a "top developer" is, but I'm not unemployed, I'm not a student, I have a wife and a son and I'm not low income, in fact being paid at least 4x the national average for software developers, my salary being on equal footing with the US, not the Bay Area mind you, but given the high cost of life there, my income is higher relative to where I live.

And I also contribute open source, a lot by my standards.

Yes my company allows open source because it is in our interest. We are contractors you see, open source bringing us visibility. I would say that open source is the reason for why I can have earnings higher than average, for one because my projects shine brighter than any resume (and I have a decent resume as well), because being able to show working code counts more than stories, but also because my work has transformed me from a full stack developer to one that is also specialized on more niche problems. Like I don't shine if you make me query MySQL, but I'm worth it if you make me handle problems of distributed systems.

But I'm not going to lie to you. It's freaking hard and it does end up eating into your family life, even though most open source I do is for helping at work and done during work hours when it's justifiable. I'm not able to sustain a constant pace. I can't do it without risking burnout. Hence I'm not one of those folks that commit every day. I can have entire months without contributions. But then when I do have contributions, shit gets serious, or in other words I finish was I start.