You are missing the point entirely. Only in America is "exercise" something you must go out of your way to do. Walking (miles) is exercise. Playing is exercise. Our kids do neither of these things independently of household income because we've built our cities to make walking impossible and dangerous, and because we've now normalized locking our kids away indoors and shoving an iPad in their face because we convinced ourselves that they will get kidnapped or run over by a car if they are ever outside and unsupervised.