My current groups try new games now and then. When I lived in Wisconsin, I had four groups. My first two groups were D&D groups. That's what they new, that's what they played. I don't even think that other games were even known to them, as they didn't actually go out and buy books or anything, they just had their PHBs and maybe another supplement or two. These two groups did share some players, as the second group spawned from the first.
My third group was made up of my wife, brother-in-law, a couple of my brothers, my oldest daugher and a friend or two. This group tried a new game at times, when I pressed them to do so.
My fourth group was made up of a friend from my first group and two players from his first group. They were, much like my first two groups, D&D gamers, only.
My current groups are much more open to trying new games, and we try a new game every now and then.