$121k is not a lot of money for someone writing compilers. And I would seriously doubt that you could just take your average developer and expect them to be able to contribute to a project like Babel in an equally productive way.
120k is a wildly high salary in Europe, and contrary to popular belief Europeans don’t just cut ties to their homeland and move to Silicon Valley just because the salary is higher. You can find a lot of compiler experts sitting safely in the UK or Italy or Russia.
