Although this statement may be true, it may also be irrelevant if there are no people in those places. That said, I'm not just being pedantic: my point is that lack of availability is far more likely to be a result of low population density than of being in the US.

Moreover, your comment fails to respond to the original point, which is that of affordability/availability to families with middle income. Poverty combined with low population density would likely result in even less availability, but, then, poverty is incompatible with "middle income".