Cardinal [0] is a wasm-based web app. What on earth would the DOM have to do with a modular synthesis environment? You seem to be imagining that wasm-based web apps implies a fairly strong connection to existing HTML/CSS/JS "pages". This is not the case and is an unnecessary cognitive barrier to thinking about what wasm (in-browser) could make possible.
And it's lacking in accessibility, just as the person you're responding to said.
> What on earth would the DOM have to do with a modular synthesis environment?
The fact that unlike people's cool and dreamy bespoke UIs drawn entirely on canvas, the DOM does actually have a competently implemented accessibility services layer that apps using it get for free out of the box.
Not to mention that you've never needed WASM to draw UIs entirely on canvas either. It's a silly idea with JS and a silly idea with WASM.
It has no accessibility features because nobody has ever figured how to do that with a virtual modular synthesis environment that is absolutely intended to be (a) extremely skeuomorphic (b) extremely visual. The same issue exists in the native world too, and isn't going to be solved by somehow connecting a DOM with the canvas.
[0] https://cardinal.kx.studio/live