I do not have a single application installed that is written in Rust. Nodejs isn't written in Rust. Firefox isn't written in Rust. That 0.1 % of the code of Firefox is in Rust (a CSS parser), doesn't justify a claim that it would be written in Rust. It is not. Also reminder that Mozilla is literally the company that created Rust, yet, after over a decade of doing so, the best thing they could create with it was a CSS parser.