Is looks like Google just needs AMP to be able to display other sites' pages on its site and mobile app. But I don't understand why they just don't take a "Read

Is looks like Google just needs AMP to be able to display other sites' pages on its site and mobile app. But I don't understand why they just don't take a "Reader mode" implementation from Firefox to produce text-only pages instead of making publishers develop a second version of their sites.