There's less data involved, with gaming it's tiny amounts, just a few bytes per second, like key presses and mouse/joystick movements, then the computer/console at their end works out what it looks like on screen, and how it behaves. With TV you're sending the whole video, which is megabytes per second, i.e. one million times as much data. Therefore, laaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaag!