an async runtime inherently requires knowledge of the underlying system which Rust remains agnostic to. Rust can be written to target bare-metal (where no OS ex

an async runtime inherently requires knowledge of the underlying system which Rust remains agnostic to. Rust can be written to target bare-metal (where no OS exists) to WASM and everything in between. If a runtime was added to the language itself you would inherently limit the flexibility of the platforms by which it could target.