I think the bigger thing would be to have more semantic HTML. <dropdown>, <tab-area><tab>Content</tab></tab-area>, <carousel><slide>Content</slide></carousel>,

I think the bigger thing would be to have more semantic HTML. <dropdown>, <tab-area><tab>Content</tab></tab-area>, <carousel><slide>Content</slide></carousel>, <rich-text-editor>, etc. Instead we've got a million immature implementations of these that are slower because they are written in JS instead of native code, slowly break over time as they aren't maintained, and typically have terrible accessibility.