为什么"早睡早起"被当作美德，而"晚睡晚起"被当作问题？ Why is "early to bed, early to rise" a virtue, but "late to bed, late to rise" a problem?

如果一个人每天稳定睡 8 小时（2:00-10:00），身体节律规律，这和 22:00-06:00 有本质区别吗？还是说这只是农业社会的遗留审美，被工业社会的上班时间强化了？ If someone consistently sleeps 8 hours (2:00-10:00) with a stable rhythm, is that fundamentally different from 22:00-06:00? Or is this just an agrarian-era aesthetic reinforced by industrial work schedules?