I don’t see how that follows. Rust could easily have a (small) standard library that is guaranteed to be present everywhere and any of a number of optional libraries that are maintained by the same team that builds the compiler and the standard library.

That’s what java spent years on getting (https://www.oracle.com/corporate/features/understanding-java...), and I think that’s the way to go for any language. It prevents the standard library from bloating, yet provides quality libraries that can be trusted. It also allows some implementations to be standard without providing all the bells and whistles. That can be useful on small platforms, and allows for ‘heavier’ optional libraries (for example a SVG renderer, PDF parser, etc)