In the US nearly everyone has no cost roaming and long distance coast to coast. Having a set phone budget is worth more to me than lower costs. I have friends who have gone for the much cheaper budget plan that only covers their local area: they love it for two months then hit a situation where either it doesn't work or they are get a big bill because they forget they traveled to a roaming area.

As other have pointed out the population density works against us a little too. Having service when I visit remote places is worth a lot too.