They do. Light still has a massive regulatory effect on the circadian rhythm, whether it's shifted slightly forward or back. Before the advent of the industrial revolution and electricity in homes no one was staying up all night unless they had to work through it.

Take a night owl and move them several time zones away, they'll end up shifting forward again in a week's time.

People with night owl genetics might have a low production of sleep hormone. Or have autism which is linked with a low production of sleep hormone.