[catnaroek]

You are badly conflating some issues here. How to implement automatic memory management is a runtime design issue. How to enforce proper non-memory resource management is a language design issue. Nothing forbids an implementation of a safe-Rust-like language with a garbage collector. Destructors would still be called deterministically, and destructed objects would still be unusable afterwards, as mandated by the language's semantics. But memory will only be reclaimed during the next garbage collection cycle.

There are other (better!) reasons against cross-language interoperability, though, such as the reduction in static guarantees to an unusable lowest common denominator.