I think this is just the decline of the birth rate. I think about my neighborhood. My kid should be spoiled for kids to play with, but couple only has one kid and the ages are spread from infant to nearly an adult, so it works out in the whole neighborhood theres only a handful of kids she can play with. I see bus stops with just 2 kids there. When I was a lid there were nearly a dozen at just my stop.
I really think because there are less kids, it's just less safe for them because people don't honestly think they'll turn the corner and there well be half a dozen kids playing basketball in the street or something.