Right, there are libraries that let you use Web Components as part of a templating system. But notice what's going on with that: WC are now just an implementation detail. You can just as well swap out the Web Component layer and it makes no difference to what's built above it. (For example, Vue CLI has a mode where it will bind to <my-app> instead of <div id="app">. Cool, but does that mean Vue is a Web Component in a meaningful sense?) That's a sign that WC aren't actually solving real problems. There are a couple of semi-useful pieces but no coherent whole worthy of the name.