wasm is only a new phenomenon and those APIs were designed without wasm in mind. Note that wasm is also slower and thus more resource (battery) consuming than a native C++ implementation. Also, Chrome is already adding audioworklets to WebAudio so it will become customizeable. Last but not least, browsers are at least a central place that can be patched. Compare this to a possible future where vulnerable wasm libraries are being used in web apps, allowing third parties to run cross site wasm based exploits. Websites can't even switch off sms based 2fA, would you expect them to keep their wasm libraries up to date?