Your comment sounds like you think open-source work would be _more_ expensive than closed-source work, or did I misunderstand? That would seem surprising to me.
I would assume some people (clearly a minority) would be willing to take a small pay cut when working on FLOSS.
E.G. could someone be paid slightly less at GitLab versus the same role at GitHub, if they believe in GitLab's principles
There are people who value open source and there are people who value assets. The point is that there isn't a single market rate for the two offers since they aren't the same thing.
I would assume some people (clearly a minority) would be willing to take a small pay cut when working on FLOSS.
E.G. could someone be paid slightly less at GitLab versus the same role at GitHub, if they believe in GitLab's principles