Given the difference between income streams, and the fact that still go to their day job, I would wager their job is an interest to them.

But if you get paid to do what you personally value, isn't that the ultimate win?

if i didn't define myself by what allows me to make a living, then i would hate my work. now i am not defining myself only by paid work. but it is part of my identity. if it wasn't i wouldn't be able to do it.

The problem with that is that, outside of our personal lives, most of our meaningful activities and contributions in society are organized as jobs at companies (or various government bodies). In my country even more so than in the US, as there's almost no volunteering here. It's just hard to feel like you're living a meaningful life without a job, or running a company yourself.