It's right now, with 1.0. Just don't use libraries that require nightly. Libraries are not the language. The language is stable. If your requirement is stability, then use the stable version of rust with stable libraries. That's what I do.

Are you unfamiliar with semver and the promises it makes?

This is a rhetorical question, as there's no way you've been around here so long without knowing what it is. For everyone else, however, the notion is that code written for 1.0 will continue to work for additional 1.x releases. It says nothing about iterating on not-yet-baked features--that's what nightly is for, and as they become baked they become part of 1.x releases. They're not breaking backwards compatibility; the major version remains the major version.

Touche! I remember a place where I worked where the first version was 3 because they figured customers wouldn't trust a version 1. I guess these guys went for version deflation.