I believe these are the talks from Steve that he's referring to. It was enlightening for me:

1. Rust's Journey to Async/Await - https://www.youtube.com/watch?v=lJ3NC-R3gSI

2. The Talk You've been Await-ing for - https://www.youtube.com/watch?v=NNwK5ZPAJCk

The first video goes into all the bits you're concerned about and all the things that Rust has tried before arriving where they are now