If future Rust versions do make semantic changes to existing language constructs, that will presumably only apply to crates built with the new edition, and crates built with the old will get the old semantics.
If we’re talking ABI-level stuff, that doesn’t require an edition because you build all your crates with the same compiler, so it can use a consistent ABI.
Swift’s ABI stability has nothing to do with semantic changes and everything to do with they wanted binary compatibility, so they could start using Swift in the system frameworks that your app links against.
Rust will never be an option in certain scenarios if the only option is to be like a scripting language and require its users to compile everything from source code.
Swift's ABI also takes into account ways to secure the ABI while evolving the language.
If you want languages that introduce semantic changes and break your code, you have many options to pick from, C++ being one such language in the same space as Rust.
How are the editions going to help when semantic changes do eventually come up in future Rust versions?