[mercurial]

Rust has a small(ish) but high quality stdlib. It does not aim to be Python. Like with any language, you have to know the ecosystem in order to be productive.

That said, sure, having a full-featured stdlib can be convenient. It's a matter of trade-offs. Having more content outside of the stdlib allows the ecosystem to evolve organically (and iterate quicker) and select the best approach to a given problem (which... could definitely have been an advantage for Python).