It seems useful for UI primitives, like a dialog, tooltip etc, that the browsers might not implement as native elements themselves. But as a building block for creating entire applications? I don’t think so.
Which means they’re always going to need to hook into the framework that’s rendering them, either to connect state, managing effects, or for styling.
I just don’t see sharing a component regardless of framework as a major problem worth solving right now. Buy into a framework and community like React and you can just drop components into your app. It’s not framework-agnostic but it works.
I'm looking at hundreds of date pickers, carousels, autocompletes, customizable selects, data tables, modals (e.g. for media previews). They've been around for as long as there have been browsers (so, thrity years or so).
Can you point at any standardisation effort around any of these commonly repeated patterns?
input type="date" and input type="color" are only now barely making it into the browser.