Update: There is an extension like this, called permanent readability: https://chrome.google.com/webstore/detail/permanent-readabil...

(though I think it strips out the junk after the whole page loads.)

I'm pretty sure readability routes web pages through their service to strip them down to the main content, and restyle them. Since this processing isn't done on your machine, it would probably be slower than loading the original page. Also, a company would never invite the amount of traffic such a feature would incur.

OK so it would make more sense to use an alternative that does it in the browser, e.g. http://www.notforest.com/.