In Spain kids are indeed less adventurous than my generation, specially in the cities, but I've never heard about someone complaining about kids roaming.
I think the number of alone activities kids can do these days to keep themselves entertained (videogames, internet, netflix, etc) is a much more influential factor.
I agree - as someone without kids in a neighborhood full of kids. In my decade of living in the burbs, I have not seen 2 children playing/going somewhere/interacting without an adult around once. I think most parents don't leave their children unsupervised AND there is a very easy alternative (videogames, internet, netflix, etc - as you mentioned).
In Spain kids are indeed less adventurous than my generation, specially in the cities, but I've never heard about someone complaining about kids roaming.
I think the number of alone activities kids can do these days to keep themselves entertained (videogames, internet, netflix, etc) is a much more influential factor.