Another galaxy might be a more apt analogy. In 1960, at the age of nine, I knew every alley in West Whittier and regularly rode my bicycle--alone--to supermarkets, drugstores, parks, the library, etc. Most of these places were located more than a mile from my home. Today, in that same neighborhood, one wouldn't dare allow a nine-year-old to play unsupervised in his front yard.
I could still do the exact same thing in 1968 at age eight in Chino. Today, an Army veteran, bodyguard and bouncer, 6 feet tall and weighing 340lbs I wouldn’t walk down a street there without at least a sidearm.