I think the issue there is that versions are arbitrary and being able to tell when a library is 1.0 is a non-decidable problem. There are lots of 0.x crates which are stable and feel feature complete, but aren't specifically versioned as 1.0.

I would actually prefer if the Rust std would not include functionality that's not essential, for example sockets don't seem essential and the standard library does not implement them in a particularly complete and well thought out manner either IMHO.