Comment by shkkmo

From other discussion in that thread, it does appear that most maintainers are employed by companies to work on Linux. That doesn't mean that all the work these maintainers do is paid, as there are also comments indicating that many of these paid contributors do work on their own time when it doesn't align with their company priorities.

I posted that statistic to demonstrate that the kernal project isn't a typical underfunded, almost purely volunteer open source project as implied by many of the kneejerk comments here.