Kernel contributors are mostly employees of hardware companies getting paid to contribute: https://lwn.net/Articles/941675/ https://lwn.net/Articles/941675/ It

Kernel contributors are mostly employees of hardware companies getting paid to contribute: https://lwn.net/Articles/941675/ https://lwn.net/Articles/941675/ It may be that in the hypothetical absence of a salary giving them an excuse, many of these individuals may also choose to volunteer, but it's wrong to call contributors "mostly volunteers" when that's their day job. Changesets from those known to be spending their own time on contributing are a relatively small fraction of the changes.