Web Components don’t offer a declarative way of updating the DOM; it’s still `innerHTML` and using DOM APIs to edit the state of the live DOM. Backbone was a hassle to manage in any sizeable app because updating the view was left up to every dev to figure out themselves. React brought a declarative wrapper around the statefulness of the DOM, and that is the killer feature that Web Components does not offer at all. Vue adopted the declarative template approach as well.
The Web Components spec was written before React and Vue were very mature, and it unfortunately shows. Web Components might offer a better primitive for higher level frameworks to build on, but I would not suggest to anyone to use barebones Web Components over React or Vue.
The Web Components spec was written before React and Vue were very mature, and it unfortunately shows. Web Components might offer a better primitive for higher level frameworks to build on, but I would not suggest to anyone to use barebones Web Components over React or Vue.