"don't break the web" type issues are not really applicable to releases of precompiled languages or applications that ship their own interpreters and don't load third party content.

Let's say you are browsing my website. Suddenly, your browser gets an update and prompts you to re-open the window. My site no longer displays correctly due to a backward incompatible change.

My site is the web and your browser broke it.

If you use a native app or service I write in rust 1.35 or whatever and there is a backwards incompatible change in a new version of rust it has no impact on your use of that app at all.