And Rust is used in various parts of Firefox now. Dropbox uses Rust in their Magic Pocket storage backend. npm uses Rust in its registry service.
Sure, Rust is not going to replace Java anytime soon (probably not at all). But for a language that has seen its first stable release only four years ago [1], Rust is a wildly successful systems programming language.
[1] Before Rust 1.0, Rust was not really usable in production due to very frequent changes to the language.
Rust 1.0 wasn't even that stable or usable in production, albeit it is of course forward-compatible. NLL (introduced with Rust 2018) was a huge improvement in overall usability, and it's likely that we'll see even more such changes in areas such as async. Rust is quite far from true "maturity" in the C/Java/PHP sense.
Sure, Rust is not going to replace Java anytime soon (probably not at all). But for a language that has seen its first stable release only four years ago [1], Rust is a wildly successful systems programming language.
[1] Before Rust 1.0, Rust was not really usable in production due to very frequent changes to the language.