The `dirs` crate has been recently forked and revived - the new home is here: https://github.com/xdg-rs/dirs (and the crate is named `dirs-next`).
Given the relatively sparse nature of the standard library, and the cost of making mistakes (std::sync::mpsc, anyone?!) I can see why this is omitted. IMO it’s a fair criticism that pulling in lots of crates is less than ideal, though.