I took the bus to school, on my own, since day two of primary school. It wasn't hard, and I don't recall anyone ever getting lost. Even if they had, it's not the end of the world; they'll find their way back eventually.
It's a peculiar American-ism to assume that children are incapable of handling themselves, and one that's been repeatedly proven false.
That and other related/similar societal changes have me scared of having children. I would get locked up for spanking my kids' butt or letting them play outside or something like that.
From about nine on, I used to beg to be allowed to sit in the car and read instead of getting dragged along through stores.
http://bc.ctvnews.ca/mobile/dad-told-children-too-young-to-r...
Children are not simply small humans, differing from adults only in size. There are significant cognitive differences between very young children and adult humans. They are not fully developed cognitively until the early 20s.
In particular, young children are not good at time management, balancing current actions against future consequences, anticipating and planning for how things could go wrong, and setting priorities.
If you start school later then households where all parents are employed and the children are not old enough to handle getting ready and out the door in the morning on their own might need to have their work schedule pushed back.
If work schedules in general then get pushed back to accommodate the school schedule change, pretty much everything else follows because work is such a big and inflexible block of time on most people's schedules nearly everything else has to schedule around it.