What gonna happen to all those engines/framework with Shadow DOM Views technologies? In short is the end of React?
That said, I have a feeling Web Components add complexity (and weight) to the render path. I doubt they will be faster than DOM diffing in the near term (although with any new web tech, there's always the possibility that they'll make available performance optimizations that can't be supported in the traditional DOM).
That's not a big deal for any one web app, but a huge deal across web development in general.
Except, it won't. They've explicitly stated they have no interest in conforming to or adapting the web components standard.
When posting strong statements, please consider including explanations, arguments, and maybe some definitions. This helps other people understand your claims, and is a big part of what makes "reason" such a powerful thing.
More information here: https://en.wikipedia.org/wiki/Reason