Async IO is solving a different problem than you're complaining about. Python is effectively multicore in nearly every use case. The only trouble is there's no free lunch -- the multicore solution depends on which problem you're facing.

So, what's the issue you're facing?

What does something not being as multicore as something else mean?

Multicore in the sense that the underlying runtime (for the lack of a better word) scales to multiple cores. Like two threads in python cannot run in parallel (like at the same time, not like second one gets scheduled if first one waits for IO or network), the way a goroutine in Golang does.

It would be great if the GC was also multicore. As it is, the task of splitting up your application into multiple processes to have more GC still involves too much friction.