If you can afford to have them just for cooling, you can afford to have them for heating as well; in fact, the capital cost may well be lower if people just used their air conditioning systems to heat as well.
The same goes for reliability - we manage to make air conditioning acceptably reliable and the tech is basically the same.
I've lived all around the US, and don't think I've ever lived anywhere with central air. Well, that's not quite true: in New Mexico I had a roof mounted swamp cooler, but that's evaporative cooling and not a heat pump. Elsewhere I've occasionally had and used a portable compressor unit, but rarely. I hadn't realized air conditioning was so overwhelmingly prevalent. Based on people I know and associate with, I would have guessed less than half that rate.
I was surprised when a colleague from Minnesota who moved to the south mentioned never having air conditioning. I'd expect that in many parts of Europe. And I've sweated it out while living there, but it's extremely rare in my experience in the United States.
I've always had central air, along with a gas fireplace for emergency heat which, thankfully, I've never had to use.