The framework controls the lifecycle of its components, connects everything together, and organizes the flow of data (in both directions) in an organic way. In its own organic way, of course.

The web components here are the stepchildren. They are clunky and awkward if they have to interact with the rest of the application. Of course, that's not the point for simple components, flows and apps. But for complex apps first is - data/control flow.

All frameworks are focused on flows control (UI/UX flow, data flow, development flow) and on complexity management. Web components are simply unable to offer any value outside of a fairly narrow niche. They're not useless, they just don't compare favorably to the frameworks. Application is not just a set of components.

Like you can have very good, even perfect tyres - but you need to have entire car to reach your place.