Sure there's competition, lots of WASM based alternatives are starting to crop up, like Bazel, Rust's GUI frameworks, Flutter, etc. I welcome those for applications more than what we have with HTML, CSS and JS now.
Replacements to HTML for GUIs tend to have terrible accessibility. I'm sure that will eventually be solved, but pure HTML solutions work right out of the box. They also do better at adapting to different display sizes.
I don't need a screen reader, but I do use Vimium, and I always hate finding an app that I can't navigate with the keyboard (usually because of abuse of JavaScript, but sometimes because they're just rendering a canvas). I don't look forward to that continuing.
How is accessibility done for mobile apps? I assume it's the same way it'd be done for WASM, it's not done simply because WASM GUI apps aren't widely used but once they are, accessibility will be developed, just as it was for HTML.
None of these are competing with what html is, but which is an open standard for rendering stuff.
Oh sure there are hundreds of modern new graphics libraries. Not a one of them is trying to be a language independent medium. None of these could ever be regarded as an internet protocol.
Not sure what you mean, WASM is a language independent medium. HTML is not an internet protocol, that would be something like HTTP, TCP or UDP. Even with HTTP, you can send any data you want, not just hypertext, which is how WASM is sent over the wire.
I don't need a screen reader, but I do use Vimium, and I always hate finding an app that I can't navigate with the keyboard (usually because of abuse of JavaScript, but sometimes because they're just rendering a canvas). I don't look forward to that continuing.