I gave a pair of talks on the background and history here. They may help? Transcripts + video:
* https://www.infoq.com/presentations/rust-2019/
* https://www.infoq.com/presentations/rust-async-await/
I'd be re-writing what's in there, so check those out and if it's still confusing, I'll check back in this thread (there's a joke here somewhere...) later.