The dream is having small self-contained web components and can just drop in to your site (the whole whole anti-JS stuff is a whole other beast and IMO unrelated to practical shortterm goals of getting web components at the browser.
What the components end up doing is still heavily dependent on a JS component building world that was built with a framework in mind and native web component integration as a future ideal implementation system. But otherwise there is no getting away from components being tied together in a wider system with heavy JS dependencies.
Basically nothing has failed. Other than maybe React and Vue et al turned out to be more practical for the above reasons and full native web components are an afterthought. They've been sufficiently simulated where it's not a big deal.