This is where a lot of high-performance stuff went in the last decade or so. HPC, HFT, AI training, several storage services, and clouds pretty much all do their networking in something other than a kernel. It turns out you can get huge performance gains by not using a one-size-fits-all networking system.

It only takes a few more steps for this model to trickle down to general applications, as HTTP and RPC stacks pick it up.