The page is all you need. A web site can be a canvas where everything can come together. And it can pull in other sites and capabilities.
We do need some new APIs for the web platform to flourish fully. Some small local host services might fill in. Or yes we could indeed enhance the browser. But the idea is that it's the page not the browser creating the experience. The page is the hypermedium.
I don't even disagree per se, i just think the grumbling is mostly irrelevant to how incredibly potent excellent & interconnected what we have is. And I think the grissly grim outlooks all ignore the incredible vectors of progress that have been lifting lifting lifting things so much higher for so long & show no signs of abating.
Letting the perfectionist neediness get in the way of seeing how amazing & competent & remarkable an ecosystem is is unfortunate.
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.
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.
Kind of a Chrome OS but not so tied with the Google ecosystem?