But you need to know when you must call this and when it's ok to not call it.

The type system won't help you with that. But if you forget to call it you can cause starvation and if you call it too often you may create too many threads.

What I see in the ecosystem is that such tricks are perceived as hacks and that it would be just better if one could just write a pure rust reimpl.

Surely there are enough reasons that drive people to reimplements stuff in rust. I think this aspect of async nudges people even further into that though.