We do have a native toolkit for the web. You put a <button> down, the browser will render a button.
But then some people don't like the button: it's not animated enough for them, the corners aren't rounded enough, the button is too skeumorphic, or not skeumorphic enough, there is too much / not enough white space, etc etc. Everyone has a different idea of what the new button should look like, and we're immediately back to fragmentation.
There are financial incentives to seeming trendy and new, and that requires constant change. The standard <button> may be sturdy and steady and not require three hundred npm packages, but it will never, by definition, look trendy or new.
But then some people don't like the button: it's not animated enough for them, the corners aren't rounded enough, the button is too skeumorphic, or not skeumorphic enough, there is too much / not enough white space, etc etc. Everyone has a different idea of what the new button should look like, and we're immediately back to fragmentation.
There are financial incentives to seeming trendy and new, and that requires constant change. The standard <button> may be sturdy and steady and not require three hundred npm packages, but it will never, by definition, look trendy or new.