To take a step back and think of our parents letting us out of the house to roam where we did without having any way of getting into contact with us is absolutely bonkers to me as a parent now.

You've bought into paranoia. In the US, most areas are far safer than they were in previous generations. Crime rates are largely down from their highs in the 70's and 80's. And even the 90's wasn't a safe time, by comparison. Even in the 90's, the whole "stranger danger" crap was so overblown that it probably did far more harm than good. The problem today is that news, both traditional and online are a 24x7 feed of "doom, DOOM, DOOOOOOOOOOOOM!" which give a horribly skewed perspective on how bad things really are. For my own kids, they disappear with the neighbors' kids for hours at a time, and we'll call them in when it gets dark. This usually involves either yelling from the front porch (I really wish I could whistle like my mother did. I could hear that whistle a mile off); or, calling around to the various houses until we find them. They don't have cell phones yet, and probably won't for a few more years, as they just don't need them. Also, I don't want to worry about an expensive electronic device ending up left somewhere or smashed.