The low-rez uploads are for the millions of people who don’t have access to anything that will play a higher resolution. If you’re on a $65 box (probably donated to you since $65 is way over your budget) then 480p is just a herky-jerky slideshow and anything higher just crashes the browser. Not to mention all of the people with low-rez eye-balls for whom high-rez is just an expensive waste.
