Entirely depends on how extensive the patches are. FAANGS will all have their own kernels with custom patches, some of which will find their way back into the

Entirely depends on how extensive the patches are. FAANGS will all have their own kernels with custom patches, some of which will find their way back into the distros, and some which are kept in-house for custom reasons. It isn't necessarily that burdensome. And I was involved in doing this at Amazon (although a long time ago now). NVidia also doesn't really need to fundamentally fork the linux kernel to do this since drivers are already a pretty hard API boundary layer. They won't need to touch the TCP/IP stack, scheduler, etc. Their version of a "fork" would be "add back the API which is being removed here".