They tried, but made the mistake of stopping once the low-level stuff was done. Welcome to Webcomponents, it can do what you currently use Angular, Vue, or React for, but it only covers the plumbing, not the actual kitchen itself, so you either have to write your own kitchen, try to mimic the kitchens that vue/angular/react/etc already made, or use a kitchen made by someone else and hope that does everything you needed.

Which is an unfortunate side-effect of the whole "JS is about giving people APIs to make things with, not dictate what those things are" philosophy. In this specific case, that leads to APIs that technically cover the needs, while also offering exactly nothing that people can "just use" for writing UIs that are natively understood by the browser.