Most homes in hot countries are not cooled with air conditioning because most people in hot countries are too poor to afford it. Even the rich 1% tend to use air conditioning only on a room by room basis, almost never the whole house.
This works if you have good fans and a lot of icewater. Using aircons too much ends up making you sick, going in and out of the heat. In Thailand we had two golden retrievers who had their own fans in the coolest parts of the house, they would sleep through the heat and then be very active in the early morning and evening.
It should also be mentioned that we are far enough south that the length of day and night doesn't change that much over the year -- the night is always long enough for radiational cooling to do it's job. That is not the case in places like New York or Boston where the nights are so short in August that it never cools down. It's always comfortable in the morning here before the mid-morning heat hits.
Contrast this with visiting hot parts of the United States where you go from your airconditioned house to your airconditioned car to your airconditioned big box store to your air conditioned office. That's a terrible way to live.
Almost every new house here includes a big air conditioner, and during hot months the euphemistically named 'load shedding' is often performed: http://www.afr.com/news/politics/sa-power-crisis-may-spread-...
Thus any improvements to (more) passive cooling technologies are very welcome
Where I'm from(Poland) summers can get stupidly hot, 40C on some days, it's difficult to sleep at night, yet I don't know anyone who has air conditioning at their house. It's a huge luxury, due to the cost of the unit + cost of electricity to run it.
I never realized how much I hated this until I started spending a lot of time in a warm country that uses AC sparingly.
However in the hottest parts of Texas the summers are brutally hot and humid even at night, and the insects are a force of nature. AC is kind of a requirement. I would imagine that if AC were magically outlawed tomorrow, 90% of the population or more of most of the South would pack up and leave by the end of August.