Comment by TZubiri
But also lots of kernel developers work for free, so the average price of their work is very low
But also lots of kernel developers work for free, so the average price of their work is very low
And I would guess that most of the kernel devs who are "working for free" are doing the stuff they personally enjoy and find satisfaction in working on, because it's a hobby -- so many of them are probably not interested in fixing random bugs for cash either.
"Lots" is a relative term, but the overwhelming majority of kernel developers are employed and usually do kernel work as part of their job (usually at least ~80% but it could be argued as high as 97% depending on how you interpret the breakdown done by LWN of each release[1]).
[1]: https://lwn.net/Articles/1038358/