Probably because the cost of an AC unit is less
Probably because we have Evan Williams. A solid, unpretentious brand of Bourbon that pleases whiskey novices and experts alike!
This.
A single AC unit kept my house in Jacksonville, FL (a 2012-built 1800 sq' suburban home) comfortably cool without skyrocketing electric bills. Modern windows helped as well.
On a related topic, I read Mark Bowden's excellent book about the 1968 battle of Hue City in Vietnam. Probably the most brutal urban combat since Stalingrad. Much of the city was built in French Colonial-style, utilizing 3 foot thick masonry walls that provided natural air conditioning and brought with this a unique challenge to the street to street fighting.