I think you have things wrong. Any other languages can have libraries be distributed as some format that would allow applications to use it, be it linux/gcc and .a files ( which are actually archives with elf/object files of the code ), or a full on library like .so/.dll.
Rust can only do .o/.dll and only have it expose like a c library afaik. Even .net has improved on the .dll and includes all its language features in it. Rust has none of that. Its not true that libraries not rebuilding are only for closed source. Its also ease of use/access and less problem prone. What if i build my library using a different version of the compiler than you and your application? I could have no problems building my library, while you cant build your application because the library i made gets rebuild and errors.
These errors happen and are all because there is no stable interface/abi and all other languages have overcome this.

Also, by default, nothing in c is rebuild unless it needs to. Thats why the intermediate .o ( elf object ) files exist, so it only has to do the relinking and not recompile and thats why .a archive/libraries in c work, because it doesnt recompile. Unless you meant the fact rust can rebuild part of a file, without recompiling it completely?

I think you dont fully understand how c compilers ( gcc specifically ) work when using multi file projects ( and not just doing gcc input.c -o output.exe ) just how i dont fully know how the rust compiler works. Also, anything using IL will always have an abi, because how else will it jump from code to IL code, so its obvious that rust to wasm will have to abide by that haha. Be it c wasm, c# wasm or rust wasm calling one another. Wasm is wasm, and you only need an exposed interface to call or include the other wasm ( c#/blazor having NativeFileReference in the csproj )

Again, i like the idea of rust, but it has a long way to go to be viable atm. And it has many pitfalls to avoid so it doesnt become the hot mess that is any framework based on node.js