It's kind of true because the WASM GC proposal still isn't finished, so Rust and C++ are the only reasonable options, and also there's no native support for calling web platform APIs yet, so there's a lot of overhead for doing web stuff and you have to use a ton of JavaScript glue code (there are tools to help, but still...).
JavaScript / Typescript will probably always have a size advantage over WASM anyway because they don't have to ship any runtimes or standard library code. E.g. formatting a string or running a regex in JS is just a few bytes but in Rust you have to ship a whole string formatting/regex library.
JavaScript / Typescript will probably always have a size advantage over WASM anyway because they don't have to ship any runtimes or standard library code. E.g. formatting a string or running a regex in JS is just a few bytes but in Rust you have to ship a whole string formatting/regex library.