Editions solve an entirely separate problem, they were never meant to be LTS language snapshots. For example, C++ is considering adopting them in addition to their current versioning scheme: http://open-std.org/JTC1/SC22/WG21/docs/papers/2019/p1881r0....
There has been discussion of a Rust LTS channel alongside stable/beta/nightly, which would try to solve that problem, but it has not been prioritized yet: https://github.com/rust-lang/rfcs/pull/2483
An actual frozen language is also a possibility, but probably won't happen until more work happens on an independent specification. Which, in fact, people are also working on: https://ferrous-systems.com/blog/sealed-rust-the-pitch/
Re:GCC-Rust: Rust frontend for GCC
by umanwizard on Sunday December 08, 2019 @02:00PM
(#21737501)
I wasn't aware of the Sealed Rust project. Very cool!
E.g., if someone thinks "I'm going to target 2015 because I want my code to run on the rustc shipped with various slow-moving Linux distros", it doesn't help, because you might still not be able to target their code, unless they specifically target an older version of rustc, which nobody does.