Do Americans really eat dinner at 6PM?

I was shocked when my friends said they eat dinner at 6PM. My family eats light snacks at 6. Dinner for us starts at 8:30PM and usually ends by 9 or 9:15PM. Another point which doesn't make sense is why do restaurants stay open till like 10PM if everyone is eating dinner at before 7? I feel like if I ate dinner at 6 I would be starving when I go to sleep at around 10:30PM.