Rust uses "Editions" (e.g., 2015, 2018, 2021, 2024) to introduce breaking changes without splitting the ecosystem. Every edition remains supported by newer compiler versions _indefinitely_. The only churn is on projects targeting "nightlies" but there's no reason you can't target a stable one for projects that need that stability.
That invariably leads to bitrot and low maintainability. It's one among many reasons why I don't use Rust.
Unfortunately quite a few useful Rust libraries seem to require nightly.
Now I’ve not extensively used Rust but almost everytime I did it ended up needing nightly to use some library or other.