[chucke]

My interpretation of what the author wants, is essentially lightweight threads in the kernel, standardised a lá POSIX , that every proglang could use as a primitive.

That'd be sweet if this were a well understood problem. Unfortunately, we're still finding the sweet spot between I/O Cs CPU bound tasks, "everything is a file" clashing with async network APIs and mostly sync file APIs, and sending that research to the kernel would mean having improvements widely distributed in 5 years or more, and would set back the industry decades, if not centuries. We learned this much already with the history of TCP and the decision of keeping QUIC in userspace.