You're conflating programming models with async runtimes, and weirdly attributing them to stabilization of a syntax sugar.
The split between blocking and non-blocking code existed in Rust before stabilization of async/await (e.g. futures 0.1 existed 3 years before, and mio is older than even Rust 1.0).
The only new thing is async-std, but that's not a stabilized part of Rust. It's just a 3rd party library. It may have been written anyway. It's relatively niche (1/10th of tokio), and you can safely ignore its existence (as far as I can tell every async-std-based crate supports tokio too, or has a direct tokio equivalent.)
I was worried that switch from futures 0.1 to std::future would fragment the ecosystem, but fortunately the whole ecosystem moved quickly, and the switch is completely over now.
The split between blocking and non-blocking code existed in Rust before stabilization of async/await (e.g. futures 0.1 existed 3 years before, and mio is older than even Rust 1.0).
The only new thing is async-std, but that's not a stabilized part of Rust. It's just a 3rd party library. It may have been written anyway. It's relatively niche (1/10th of tokio), and you can safely ignore its existence (as far as I can tell every async-std-based crate supports tokio too, or has a direct tokio equivalent.)
I was worried that switch from futures 0.1 to std::future would fragment the ecosystem, but fortunately the whole ecosystem moved quickly, and the switch is completely over now.