The problem is Wasm is not improving nearly as fast as predicted here. We don't have DOM manipulation so we will still need JS regardless as glue code, or just eschew HTML and CSS altogether and render everything on a canvas as Flutter and some Rust GUIs do but that's a shame to lose the feature set of the web.

People choosing Flutter would say the uniformity of a canvas across all browsers is more valuable than gaining the inconsistently implemented web feature set.

The DOM and JS are joined at the hip - the DOM APIs are designed assuming JS is used to access them, and the design of JS and some of its more “unique” features is partly because it was designed for use with the DOM

JS is just so much more approachable than WASM. You can debug it on the fly, feed it to an LLM, there is no wrapper, it's just so much easier to tinker and work with it.