that's just myth, my 1yo wakes around 630-700 and 3yo would sleep even until 0720 if i would let him (sometimes i have to go to his bed and need alarm to wake us and not miss kindergarten) and i know luckier people whose children wake up even later and we are putting children to bed around 1915-2000, i don't think it's extremely late, can't really imagine much earlier unless moving dinner before 6