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.

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.