Back in the day, only adults complain of sleep issues. From your productive adult years to later in life as a resident in a nursing home, sleep can evade you and leave you wide awake at night.
On the other hand, children enjoy more sleep than adults. No or lesser responsibility allows them to sleep longer hours. Their active lifestyle of play and make believe also leave them exhausted at the end of the day, making it easier for kids to drift off to sleep once they hit the sack. And it makes sense considering their body needs enough sleep and rest to grow big and strong.