I’m American, and I have to eat dinner by 5 or 5:30 at the latest. That’s just how I am. However, I wouldn’t extrapolate that to make a conclusion about all Americans. In fact, most of my American friends find my dinner timing quite frustrating. If I have an event dinner, I might even need to pre-eat ahead of time to avoid getting hangry. I often eat dinner before Mother even eats what she calls her “lunch” between 4 to 7 PM :-) (note that she doesn’t eat a meal after that, so it’s just semantics).