720 TVs may be small, but that is the broadcast standard today. Keep in mind they are using $50,000 cameras with $30,000 lenses to broadcast that picture. Have you ever edited HD footage in a standard, run of the mill computer?
Your information is *way* out of date. In my local (Dallas) market, digital broadcast channels are 1080p30 at a minimum with 720p30 left as a deprecated resolution. Even my evening news from local affiliates is in 1080.