I have looked up different cities and stuff, too... I looked up my brother's house in the Rockies, and he's about at 8500 ft above sea level. I just assumed that because you could barely make out roads that it was because of the lack of being able to change the focus at that elevation, but maybe it's like you guys said and they just don't get great pics of rural areas.
PS - his house he said is at 8500, but on the GE site, it says it's aroudn 12500... so elevations may not be the best reference.