How much of Linux development is actually volunteer work? I assumed the bulk of the work was done by professionals whose employers were paying them to work on the kernel.
In that case, I could see a non-trivial number of those developers being in a situation that their other work commitments were slowed down, so kernel development got a bigger chunk of their time.
Not a lot, you can see it on the development statistics that LWN releases for every major kernel releases, for 5.7, it's only about 13-14%, so most people working on the kernel do indeed get paid for it.
