You wrote:

> The job wouldn’t have been done. They would have needed threads. And mutexes. And spin locks. And atomics. And semaphores. And message queues. And - in my opinion - the result would have been a much worse language.

My point is that you do need mutexes, spin locks, etc with async as well, given that you have a multi threaded platform. So no, we have basically 2x2 stuff we are talking about with very different properties (async/sync x single/multi threaded).