The stable ABI in Rust is called the C ABI. Which means you can write C compatible dylibs/.so in Rust that can be used by any language with a C FFI. This is used in the real world for seamless rewrites of existing dynamic libraries in Rust - librsvg being a well-known case. You don't need all the hacks OP is talking about.
Sure, dropping down to a C interface is easy enough, but far from ideal. So much of Rust's expressive power is lost by doing so. What would be the downside of providing a stable ABI for an edition? It seems to me it resolves both sides of the argument on stable ABIs. By the way, I'm mostly thinking about Rust -> Rust dynamic linking.
