I sort of agree with you to a degree, but I also think that the browser having knowledge of the size of your viewport actually has some use. Now, I would probably like it more if all webpages were just made with the restriction of not knowing the viewport size since that would dictate some design choices. Cellphones can just scroll around the page anyways. They should be second class citizens on the internet anyway in my opinion. The smartphone has been one of the worst inventions for the human race with how much it seems to isolate a lot of people more than connecting them.