School and work hours is a very similar problem to the metric system. Even though there's a more efficient system, the switching cost is significant in that you're out of sync with all those that don't make the switch, or don't make it at the same time as you.
Once the majority or a popular minority start using later work/school hours or the metric system, then there will be a catalyst for change. But for those early adopters there is a significant burden of extra communication that needs to take place.
Or perhaps it’s the opposite. It makes more sense for planners and idealists that everyone would sleep the same amount and wake up and work at the same time (just like they would like us all to use units divisible by 10), but reality is organic and messy and it turns out that the old traditions (segmented sleep, sleeping to the day/night cycle) had it right all along.
Glad it didn’t turn out badly, but from a sleep cycle perspective it’s normal. Kids usually have fairly early sleep cycles, and as they age it gradually gets later, peaking around late adolescence where it can be three or so hours later than an adult. After that, it shifts back to normal over the next decade or so. Aparantly this has been observed not just with humans but in various animal species as well.
But there are various disorders where people either have unusually late or early sleep cycles that can be up to several hours different from normal.
Once the majority or a popular minority start using later work/school hours or the metric system, then there will be a catalyst for change. But for those early adopters there is a significant burden of extra communication that needs to take place.