[blub]

Almost any language can call C functions and we don't call all languages backwards compatible with C when they can merely interoperate with it.

Objective-C and C++ are the only two languages which offer backwards compatibility. AFAIK it's complete in the case of the former and there are some limitations for the latter.

None fix the problem like Rust does, but it's worthwhile to examine why: typical companies and developers have an aversion to paying for tools and for anything which slows down development. That's why usually those tools and languages which are reasonably user-friendly are more successful. Ironically that's both an advantage and a problem for rust: it's nicer to use than some C tools, but still not user-friendly compared to alternatives like Go or Java and in some cases even C++.