[necessary]

Maybe not compared to what browsers were a decade or two ago, but I think the definition has changed. These days browsers are just sandboxes with convenient tooling for finding, downloading, and running arbitrary code. And I don't think that's a bad thing: that's what allows Photopea and Figma to exist in the browser at a moment's notice.

Once you generalize the definition of browser, both ends of the spectrum coexist: from basic HTML pages to fully WebGL rendered WebAssembly apps.

[actionfromafar]

It's already that, but what I got from the OP was to add native controls, like what is necessary to (re-)implement accessability. (That builtin accessability mechanism of the browser itself won't do for various reasons.)