That you don't have to rebuild such apps from scratch on WASM is exactly the point. You can compile legacy codebases in C and C++ to WASM. It was designed for

That you don't have to rebuild such apps from scratch on WASM is exactly the point. You can compile legacy codebases in C and C++ to WASM. It was designed for that. Doing that on the JVM requires "research-level" techniques because the bytecode has a completely different design.