Standard library omissions aren’t there just because.

For almost any functionality missing in the standard library, you could point to 2-3 popular crates that solve the problem in mutually exclusive ways, for different use cases.

Higher level languages like Go or Python can create “good enough” standard libraries, that are correct for 99% of users.

Rust is really no different than C or C++ in this regard. Sure, C++ has a bigger standard library. But half of it is “oh don’t use that because it has foot guns for this use case, everyone uses this other external library anyways”.

The one big exception here is probably async. The language needs a better way for library writers to code against a generic runtime implementation without forcing a specific runtime onto the consumer.