Basically we need hardware that works a lot more closely with the OS, and an OS that works a lot more closely with modern language semantics. The problem with t

Basically we need hardware that works a lot more closely with the OS, and an OS that works a lot more closely with modern language semantics. The problem with the general abstractions you call out (correctly) as inefficient, is that they're stuck in the 80s, and they gotta work with code that looks pretty much like compiled C binaries from the 80s. Green threads at the language level and so on is a stop-gap in the long-term. Everything has to align together, and then native thread switching will be just as (or almost as) light as green threads. To be a tad more specific, basically we need hardware+OS to provide us with a model that's pretty close to what the Erlang VM emulates.