Most all of the open source maintainers I know would LOVE to work on their projects full-time for a modest wage. But developers, teams, and companies have no interest or mechanisms to support that model... which is why VCs swept in to try to corrupt open source into a twisted product lead growth strategy.
Sorry to rant. I'm so glad mrdoob could do all this amazing work without needing revenue from it. I just get bristly at anyone who claims maintainers wanting to focus on their passions are "profit-driven".