Games are the first type of application to use this, but won't be the last. If you can run AAA games in a browser, you could run Photoshop, Maya, programming IDEs, and other professional tools. It's not just another framework.

In 5 years...

Games, yes, but this would probably also open the door to high performance web apps.

The web will always chase after native unless you truly remove the web portions. WebGL might be the best example of getting close, but for the meat and potatoes of UI, there's very little comparison when looking at the DOM.

This times a million. Addressed perfectly: https://xkcd.com/927/