> but "give a name to a re-usable set of styles for a component" is pretty much as fundamental as you can get.

Yes. And as 30 years of CSS show, it's not enough.

> Sure, sure. except for the inline styles everywhere. And the fact that everything is literally being repeated all over the place.

It's not repeated all over the place, because in your codebase you have a single place where component A is defined. A single place where component B is defined etc.

I don't see you complaining about having to repeat the same CSS properties (padding, margin, display etc. + responsive styles + hover/disabled etc.) for half of the components when writing vanilla classes.