First of all, the battery life improvement with 720p vs 1080p is negligeable. Screen size and brightness matters more. Second, there is such thing as a 'good

First of all, the battery life improvement with 720p vs 1080p is negligeable. Screen size and brightness matters more. Second, there is such thing as a 'good enough' battery. For most people, this has been achieved with the current crop of big screen, high res phones. Not sure why you think people would accept lower resolution for an extra half hour of battery life...