While the cadence may be faster, the pace of language change in Rust is slower than other popular languages such as C++ or JS.

I mention the reason in my prior comment: to allow people to continually upgrade their compiler version without needing to change any code. Rust doesn't have a stable ABI, so all crates in a Rust project ultimately need to be built with the same compiler (and furthermore, crates must always be able to interoperate regardless of which edition they're on). That means that every new version of the compiler needs to support every old edition, because the alternative is to have users stuck on old versions of not just the compiler but also on old versions of dependencies that have since begun using features only supported by newer compilers. In Rust's case avoiding such a fundamental fracture in the community was more important, since, after all, there's still nothing stopping anyone from voluntarily sticking with an older version of the compiler if they're willing to deliberately endure such a situation.

> (And has a number of other disadvantages too, like constant cognitive load having to re-learn the language every 6 weeks).

This is quite hyperbolic. Rust introduces no more features than any other language, it simply rolls them out on a more fine-grained schedule. Furthermore, Rust hardly requires re-learning every six weeks; a "feature" introduced by a new version is often nothing more than a new convenience method in the standard library. The fact that we have established that Rust goes out of its way even to keep "old" code compiling and compatible with the rest of the ecosystem should demonstrate how little it demands that users re-learn anything.