Kind of disagree, suburbs I see most of the kids literally played in the streets or alleyways. Usually it only stops in winter and mostly because it gets dark shortly after school and the extreme cold.

Plus the actual article itself is commenting on a decline of socializing that's occurred in the last 30 years. But suburbs have been predominant the US for around 60 years. And there's similar declines occurring in more dense cities like NYC and Washington. If it was strictly a suburb problem then someone living in Manhattan shouldn't have been affected but last I heard even those cities are affected.