This is missing the forest for the trees.

There is no one always-right way to get best performance for every program. You can argue about it all you want. Thread-per-core benefits/downside is a typical "it depends" discussion.

The problem is that using `async` in the first place is a premature optimization. 99% of Rust programs are not redis, linkerd and alikes. They are some CLI tools or Web apps that could have been written in Python or Ruby, and they would still be fast enough.

So why as a community we abandoned blocking IO Rust and everything is async now, and developers are just doing `#[tokio::main]` by default on everything?