The thesis is that javascript-compatible source will be the substrate of the future. A javascript engine, though one highly optimized to efficiently interpret a compatible subset, is a potential universal platform of the future despite generic javascript being a terrible substrate.

WASM fundamentally rejects this by creating a new javascript-incompatible substrate that is actually designed to be a low level target. Claiming WASM is confirmation of the thesis makes as much sense as claiming that a future where everybody has a Rust interpreter in the browser is confirmation of the thesis.

If you are arguing that, then you are just arguing that web browsers will run code in some form in some language as they already do. As the video is clearly discussing a “surprising” possible future, it makes little sense for it to be consistent with literally business as usual and literally every possible future.

Just asking out of curiosity.

Also, the screenshots I've seen of webOS makes me long for a revival... not only on smart TVs