I agree with every thing you said and the situation is getting like it is in the US, here in the UK.
We have a huge rise in childhood obesity, when I was growing up the "fat" kids in school was one in 50. Now it is closer to one in ten. (I was not a fat kid.)
Our kids do have a poorer diet, far too much sugar and aggressive advertising of junk food to kids on TV.
But they also do not play out, you don't see two ten years walking together to the park or racing each other to get there.
Kids are soccer mad but they don't play it much on the streets or estates, the play in on their X boxes instead.
Parents are scared of letting their children out, for fear of drugs pushers and thugs, but indulging them in the highly addictive drugs of high sugar and high fat diets, whilst veg out in front of the tv.
When I was growing up I walked up a steep hill to school every day five days a week for seven years and back in the afternoons, starting aged nine. And we did go to the sweet shop on the way but we didn't get fat because we only got a few penny sweets, not cans of fizzy drinks or chocolate bars.
Now most children even in urban areas get driven to school and picked up afterwards, missing out of basic exercise.
When I was a child was had times without a TV, I would throw a tennis ball against a wall on practice handstands etc.