The myth of childhood happiness flourishes so wildly not because it satisfies the needs of children but because it satisfies the needs of adults. In a culture of alienated people, the belief that everyone has at least one good period in life free of care and drudgery dies hard. And obviously you can't expect it in your old age. So it must be you've already had it.
The Dialectic of Sex: The Case for Feminist Revolution (1970)