Why is it conceivable? Why this tremendous change from my own childhood, in which it was normal for us to wander far and wide, unsupervised, from as young as 6 or 7? Here are a few reasons:
(1) The decline of community. In my childhood all the neighbors knew each other and would keep an eye on each other's kids. The boundary between home and not-home was more fluid, more gradual. The neighbor's yard or the cornfield at the end of the street was still home territory.
(2) Relatedly, when people are tied together in community they are not so prone to call upon remote authorities such as CPS or the police. They go to each other first, using informal means of negotiating social disputes, enforcing norms, and taking care of each other.
(3) Our society has become habituated to control, and uncomfortable with uncertainty and realm of the indefinite. A child, accordingly, must be under someone's official supervision at all times. Whether it is the bus driver, the school, the day care worker, or the camp counselor, someone must always be *in loco parentis*. Someone must always be in control. The child must always be accounted for. There is no room for the liminal space, the exploratory zone, the adventure, the unknown. The same mindset also manifests in the expansion of legal liability into every aspect of public life. In a world under control, if something bad happens, it must be someone's fault.
(4) Safety has become a top priority in our society, more important than freedom, more important than fun. Writ large, that priority informs the national security state. Why should safety be our number one priority? What kind of person puts self-preservation above anything else? A person disconnected from life purpose, disconnected from service, and disconnected from the creative impulse, that's what kind.
Our economic system, educational system, and metaphysics all promote that disconnection. The dominant teaching of both economics and evolutionary biology is that all beings are driven to maximize their self-interest (in economics, financial self-interest; in biology, reproductive self-interest).
Unfortunately, without an element of danger or uncertainty there is no such thing as an adventure, and therefore no opportunity for children to explore their boundaries, develop self-confidence, and become comfortable with uncertainty. Constant supervision transmits the implicit message "You are not trustworthy." No wonder untrustworthiness is what they enact when they become teens.
When real adventure has been cut off, what is left? Fake adventures in the form of video games and virtual realities on line. These are consequence-free zones in which nothing really bad can happen, and nothing you do really matters. In raising my own children I've done my best to limit screen time and make them go outdoors -- no easy task when most of the other kids are safely parked in front of their screens. And, it turns out, a terribly risky proposition. I'm not so afraid of kidnapping, drowning, or any of the other terrible things that truly could happen to my unsupervised children. They could happen. Life isn't safe. What I have been afraid of is what happened to this Florida boy.
It's time to reclaim the kingdom of childhood. For me personally, I'm seeking to move with my family to a place more aligned with my parenting values. But ultimately we need a shift in values everywhere.