Because he gets to make a living doing something he likes, probably.

Why bother doing anything difficult or burdensome if one has the option to take the easy route?

This man sounds like he has a real passion for what he does. He's been doing it for quite a long time, and like you pointed out, he could've checked out and got a salary job at some company. He didn't. He gets to live his life doing something exciting that he loves.

Living your life always doing what's safe doesn't sound very intriguing.

Making your own thing and not having to deal with others is worth a lot.

Passion. You’re right - its a terrible ROI.

But the answers passion. And that’s fine, just don’t complain about income then (which the author doesnt seem to be doing).