There’s been a lot of movement in this direction for CSS which is great, but it needs to happen in HTML and JavaScript too. Just a few cycles of implementing popular libraries as base browser functionality and adding better widget primitives would do wonders to reduce complexity and bloat.
https://github.com/Flipboard/react-canvas
React is the Simpsons of web tech (Referring to the "Simpsons did it meme" if that wasn't clear).
There are a lot of interesting renderers for react, some of them are even maintained: https://github.com/chentsulin/awesome-react-renderer
But this is the antithesis of FE culture. When FE culture spun up there was a lot of mocking of javascript devs as not "real" devs. I think they felt the need to reinvent CS so that they could show they were legitimate. They never really recovered from that.
The end goal here would be to have a basic reactive UI development toolkit complete with a full spread of ready to use widgets with nothing but a plain text editor and a browser.
That won’t meet everybody’s needs of course, but even those still using third party libs would benefit since things like React could be lightweight “sugar” libraries built on the browser APIs instead of hulking behemoths with a fractal spiral of dependencies.