I don't think there is anything special about getting up early
This is not meant as a slight to those who really have to be up early. Or even to those who do better when they get up early. I would be willing to wager a small sum that it would be possible to find 23 people who succeeded by staying up late, and almost impossible to sell a book about them.
I am a natural night owl, struggling to manage in a world organized around larks. I suppose I could say that I get up early, but it's really that it takes me a long time to get up. I have a layered approach to waking up on a work day. The lights come on at 5:30. The first alarm is at 5:40 and the second is ten minutes later.
When I can.. which is almost never anymore... my most creative time is between midnight and 3:00AM. But to meet that morning schedule, I have to be in bed by 9pm. Every once in a while, my body rebels at this treatment, and I will find myself unable to fall asleep, no matter how tired I am until three or four in the morning.