The idea that Rust has a small standard library is a weird meme. Rust has an enormous standard library. Look at any Rust release and you'll see dozens of new library APIs added, and consider that Rust has about nine releases a year, meaning that Rust adds over a hundred APIs per year, and has consistently for the past ten years. Rust frequently adds things that obviate popular crates, most recently the cfg_if crate was made redundant by the new cfg_select macro. And half of every dependency graph that people wrong their hands over are actually first-party external crates provided by either the Rust organization itself or by known contributors to the project. When people say that Rust has a small standard library, mostly they seem to just mean that it doesn't include a webserver.
It still lacks basic functionality like a JSON parser, regex, directory walker, rnd generator and cli arg parsing.
I won't mention lack of date/time lib because that's complex and changes often.
That's why projects end up with 100s of crates, sometimes 1000s.
This might not be a well received fact in Rust community, but it's a fact nonetheless.