This. Growing up, I was only allowed 1 hr of video games or TV per day. And on nice days, I was ordered to play outside. I grew up with a love of outdoors, sports, and have always been in good shape. My cousins were encouraged to stay in and play video games and never allowed out alone. We are similar age and genetics, yet they are both overweight and unhealthy. Whereas my sister and I are healthy.
I know it's anecdotal, but my families experience sure matches your centennial common sense.