Yes. He would more than double that by joining at the E5/L5 level at Facebook/Google, which he's almost certainly qualified to do. But given the success of Vue.js and his status in the JS community, he'd probably be a marquee hire at the E6/L6 level.

However he would be sacrificing a lot of autonomy to do so, because Vue.js would effectively be developed under the same corporate stewardship model as React and Angular. He doesn't make as much money as he could given his accomplishments, but he maintains broad control and ownership over his work.

Likewise his Patreon sponsorships can increase over time as Vue.js increases in adoption. And if he wants more income, he can take on lucrative consulting contracts for Vue.js deployments with large tech companies. A few of those per year would likely meet or exceed everything he's bringing in through Patreon.

I agree. I earn something comparable and I'd say I provide far, far less value to any community or even my employer.