Easy: web components have not implemented a single part of the original promise [1].
It's not Web Components that are happening, it's the dozens of frameworks required to make them work that are happening.
Even mixpanel's library "does so by providing an easy-to-use state management and rendering layer built on Virtual DOM (the basis of the core rendering technology of React). Through use of the Snabbdom Virtual DOM library and first-class support for multiple templating formats" [2]
Web Components are a very low-level extremely limited crummy DOM-based API that no one in their right mind wants to use. They are not happening.
It's not Web Components that are happening, it's the dozens of frameworks required to make them work that are happening.
Even mixpanel's library "does so by providing an easy-to-use state management and rendering layer built on Virtual DOM (the basis of the core rendering technology of React). Through use of the Snabbdom Virtual DOM library and first-class support for multiple templating formats" [2]
Web Components are a very low-level extremely limited crummy DOM-based API that no one in their right mind wants to use. They are not happening.
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[1] https://fronteers.nl/congres/2011/sessions/web-components-an...
[2] https://github.com/mixpanel/panel