I think those two are exceptions. A lot of my family lives in Mexico, and they definitely don't live anything like the girl in Mexico City, much less many Americans. Most of the houses are humble, but not nearly as luxurious as many standard American homes.
And thinking more about it, I don't really know that I can speak for most Americans. I'm sure that there are a whole lot of people who live similar to you and me (assuming you live like a lower-mid to upper middle class person). I'm not really sure how many there are in this country who live in a dilapidated home like the American girl, but my guess is that it's a smaller percentage of our population.