I see where you're coming from but I think there's also a lot of unacknowledged variables in play here that get glossed over because of a focus on the outcomes such as dead kid vs. live kid. For example, I'm wondering if the same rules and recreation structure that result in a dead city kid result in a dead rural kid. A lot of environmental factors including traffic, neighborhood crime, average physique (in areas where children might often participate in their parent's physical labor), etc. could all create outcomes that are generally more potentially lethal for a child raised in a densely populated metropolitan area than for a child raised in a rural area.