Of course, most kids lived on farms, some even had chores before going to school, and early to bed, early to rise was normal.
We had a few antenna TV stations, no cable, VCRs weren't around for the average family, and of course no Internet.
We also didn't have city street lights / ambient light, street noise, the sound of neighbours.
People have gotten up early to do farm work for aeons, and go to sleep early too. In fact, to be more precise, staying up past 8 or 9pm is an urban / modern aberration.
Point is, staying up late is the problem. Nothing more.
Now of course, society has changed, so maybe change is needed. However, there is also a lot of counter literature on even TV as a sleep depriver. And now we have phone in bed, with a glowing screen, keeping a mind active.
My point? OK, change the time. However, will kids just stay up even later?
Or, as they do now, will they think "I should go to sleep now, or I will be tired tomorrow, but just one more text..."?