The only failure of WASM is that it was overhyped beyond all reason. It's "just another" virtual instruction set, and for that it turned out pretty great. It's supported by Clang and by all browsers. That's already enough to make the whole idea work.

You don't hear much about it because for the people using it, web+wasm is "just another porting target", like Windows, macOS or Linux. WASM has become 'normal' and that's a good thing.

The main risk these days for WASM is feature creep, the spec is getting bloated with optional features (garbage collection etc...).