It's not just old-time fiddlers. Go to any Irish session and see how reels pre-dominate. I played for a St Andrew's night ceilidh once and had Sean Casey in my band. He admitted to not having played jigs for years and was surprised at how may we used. Not that he couldn't play them -it's just that he didn't think to play them.

Think of pop and rock as well - most music there is in double time rather than triple.