I don't buy this, considering that wasm still doesn't actually have access to the Web APIs that JavaScript has access to (and relies on JS to even be loaded in the first place).
In my opinion, if that's what counts as being a supported language, then JS was never the only supported language to begin with since you could always compile other languages to run on the web through JavaScript (for example Emscripten with the asm.js target predates WebAssembly). The only thing that wasm currently offers over the previous status quo is that it's faster (for some workloads).
I don't buy this, considering that wasm still doesn't actually have access to the Web APIs that JavaScript has access to (and relies on JS to even be loaded in the first place).
In my opinion, if that's what counts as being a supported language, then JS was never the only supported language to begin with since you could always compile other languages to run on the web through JavaScript (for example Emscripten with the asm.js target predates WebAssembly). The only thing that wasm currently offers over the previous status quo is that it's faster (for some workloads).