Why Aren’t Underground Homes More Popular in Oklahoma?

Given that Oklahoma has Summer and severe weather most of the year, it's a wonder why underground housing isn't more popular. Granted, there was an underground movement back in the 80s that really never took hold, but there are a handful of these houses in SWOK.

I know, I know... The well-documented problems with these houses are pretty well known. Ventilation issues that cause mold and that familiar wet smell aren't anything to look forward to - but this day in age, the technology and how we understand ventilation, heating, and cooling can completely take care of that.

Could add up to real savings.

You see, the Earth stays at a pretty constant temperature, about 55 degrees. You toss a house under a few feet of dirt, you're benefiting from that constant the whole year round. You can effortlessly keep it warm during those few weeks of Winter we get, and keep it cool the rest of the year with minimal air conditioning. It's a win-win, yet we still don't see too many underground houses.

Why not?

There is an equally long list of cons to argue against the pros. Maybe Oklahoma experiences too many earthquakes. The ever-shifting clay soils are pretty unstable too during the wet and dry seasons, but even so, if the science could get it right, would you live underground?