We had all that stuff growing up and we were skinny. I grew up in the 60's and 70's. I still think its lack of exercise (too much computers, video games and cable tv). We were outside playing all the time and hardly ever watched TV except for nighttime just before bed. But that's only my opinion.
I think you are right. I don't let mine run the streets, but we fenced the backyard in so that they can come and go as they please back there during long summer afternoons. The kids would play out there all day if given the chance.