I like Rust and have an ambition to learn it as well (I've had a few false starts...). One of my issues that I have is that every (slight exaggeration) library that I seem to come across is still at version 0.x.y. Take this library as an example. 0.1.0 was released in 2014 and it still hasn't had a 1.0.0 release, is there an aversion to get to 1.0.0 in the rust community?
Serious answer: For some, they do change semi-often and don't feel compelled to declare stability. In other cases, it's a stable + widely used 0.x package, and bumping it to 1.0 usually implies _some_ kind of breaking change. (I don't know if that _should_ be the case, but I know that if I see a dependency has bumped from 0.x to 1.0 I'm going to be cautious and wait to update it until I have more time).
In general: People usually aren't too concerned about it.
This list's Zig as an entry, despite the Zig project having very clear plans[0] for a 1.0 release. That's not 0ver, it's just the beta stage of semver.
Yes, in rust, the package manager has built in rules about when to update a package. It won’t auto update a major version change because it implies a change that breaks something. As long as your package is safe to auto update you don’t want to change the major version number.