Because life is just too dangerous to live!
Really, this is the safest time to live in the United states there has ever been and I'm guessing that's true of the civilized, "first-world" in general. Your kids are more likely to grow up big and strong and to live longer than you do, just as you're likely to live twice as long as folks did a hundred or so years ago, but you'd never know it to listen and to read and to feel.
Have you seen the recent car commercials where the distracted young mother with child in the back seat ( kids can't ride in the front seat any more) nearly rear-ends another car but is saved by automatic braking? Last night I saw another one where Young Mother gets into oncoming traffic on a bridge but the car saves her at the last moment. Self-driving cars are being tested now and self parking cars are a reality. Cars warn you of other cars in your "blind" spot you would have seen anyway if you were looking and we're supposed to be as giddy and elated about it as an American who just worked "selfie" into a sentence for the first time. We're in terrible danger because learning to drive safely is beyond us and the future must be about cars that drive themselves without participation from you. Driver training? What?
Oh, brave new world that has such cowards in it! What a wonderful world where no risk of any kind is permitted or tolerated outside the world of video games, where a woman can be arrested for letting a 7 year old walk to the park. Yes, arrested, not scolded or cautioned -- and she faces 5 years in the slam. Maybe she should tke the kid with her -- it's safer behind bars.
No, the joy of driving an open car, a sleek powerful masterpiece of engineering down a country lane, the joy of riding a bicycle unsupervised when you're 7, of walking to the park on a Summer day -- there are parents who won't let their kids play in their own suburban yards unsupervised, whose every moment is scrutinized, analyzed and proscribed lest there be any danger at all of any kind.
How beauteous mankind is! O brave new world,
That has such people in't.