Maybe that's how things have become but it's certainly not how I grew up. My going to visit my grandmother alone was unusual, not a cause for alarm. I was 7, it involved public transit and crossing major streets. I was trusted to handle it, never had any issues other with getting on (drivers blowing past, not realizing I wanted on)/getting off (this was back when there was a pull cord at adult height.) Even tried using public transit to get to school (didn't work, too many drivers blowing past.) I've been in many other countries--and seeing young kids on the bus is the norm.