I see your cgo analogy but at the same time it's much less pronounced there since the programming interface is the same, the programmer is supposed to assume everything will work as it should (even if it doesn't always). In this case it's a different programming interface and I think that stresses the issues.

Regarding your comment on preferentially having control over blocking/async code. I think that's right. At the same time, some C++ programmers would say that they prefer having to think carefully about how memory is managed in there program (say, for the benefit of fast no bounds checking). C++ draws a line, Rust draws a line, Go draws a line, Java draws a line, and Python draws a line. These lines are somewhat about technical superiority and somewhat about programmer identity/preference but they are mostly about domain-specific constraints and necessary tradeoffs. This futures-based approach will be sufficient (if somewhat inconvenient) where Go/Erlang can't be used, e.g. where GC pauses are absolutely intolerable.