I think the difference is North American people usually will train the baby to sleep on their own very early, e.g. before 1 year old. That's why the child will sleep on their own and have a very regular schedule, like going to bed at 8pm (my daughter goes to bed at 8pm-830pm too and sleep on her own).
But for Chinese people, they like to sleep with the child, or wait till they are sleeping. In these cases, the children will "play" (or fight sleeping) till the very last minute and get very very tired before going to sleep, e.g. going to bed at 10pm or later. In these cases, they may be too tired to have a good sleep.
I hope this may help you.