Hah! Good point, I didn't think about that.
Although IMHO daycare has plenty of benefits, and I actually do know of people who send their kids to 1/2 day daycare just for the educational benefits and socialization, so that is still 1k a month or so.
I've also noticed that the stay at home parents tend to enroll their kids in more activities, the cost of which quickly adds up.
Being with a toddler 24/7 is a ton of mental work, especially in modern western societies where we don't have extended support networks of family and friends.
If you are retiring early, why are you paying for daycare?
Many people would love to retire early just to be able to spend time with their children.