I'm a millenial. At 7, I was allowed to cross the street and walk within one block (quiet suburb). At 12 I went to a school outside my immediate area, and I took the city bus there on my own. At 14 or so, I was allowed to travel anywhere in the city, provided my parents approved. Went to a concert with friends around that age. I took my first overnight trip away from home on my own at 16 to go visit a friend who had moved.
That experience seemed normal to me at the time, but me and my friends may have been the tail end of that degree of freedom. Funnily enough I rarely exercised it. My parents encouraged me to explore more than I did. I was a very introverted and nerdy type who spent most of the time indoors. But I would spend my weekends and summers with my friends. And my parents wouldn't usually be willing to drive me once they considered me old enough to walk there or take the bus.