It's true. The big reason that kids don't go out and play anymore is that there are no kids outside playing anymore. I live in a neighbourhood where I'm only a few blocks from 2 elementary schools and I never see any kids out playing.
https://people.com/parents/mom-investigated-dcfs-letting-dau...
https://www.parenting.com/blogs/show-and-tell/hayley-parenti...
https://www.theatlantic.com/national/archive/2014/07/arreste...