Because its not necessary. Unless there are massive amounts of under 13 year old kids that are able to buy a $1000 phone, I'm pretty sure its the parents buying it and then handing it over to their kid. There are already tools in place when you set up the Apple account AND the phone, to lock it down and require parents ok to get apps. Parent your kids. Quit making these tech companies do it because people just want to sit there kid in front of tv, like they did years ago, or computer, or in today's world, tablet or phone.