Library developers can afford to deal with complexity much more than users of libraries. Offloading such work on highly skilled people developing the basic infrastructure is surely the right approach.
I totally agree that library developers are the ones who _can_ handle complexity, but I have found even some of the top Rust devs are making async mistakes -- either the APIs are not correct from an async perspective, or there are basic bugs like losing wakers. The latter is so common it's not funny.
