Rust cares about a subset of PL ergonomics, sure. But it is not true that Rust as a project is an experiment in hammering down costs on ergonomics as small as

Rust cares about a subset of PL ergonomics, sure. But it is not true that Rust as a project is an experiment in hammering down costs on ergonomics as small as possible. If that were true, the Rust toolchain wouldn't be what it is.