I'm no expert, but I'd bet this has something to do with insulation and/or economics.
Is there a good way to insulate concrete construction? Where I live, we'll regularly get 100+ degree temps during the peak of summer and below zero temps during the worst days of winter.
I also wonder about concrete being overkill. In another thread somebody brought up the idea of turning a Boeing cockpit into a roll cage. Same idea here. Concrete might be many times stronger than wood, but reality is that it still wouldn't withstand a direct hit from a tornado, and stick built construction is adequate for the common threats here, like regular thunderstorms and blizzards.
Like most things in life, there's probably reasons why things are done the way they're done.