A child in the suburb will need a chauffeur to get anywhere outside their immediate subdivision, and sometimes within it. Children are perfectly capable of taking public transit and using their two feet, though.
Cities like SF tend to be okay for families in two different (and polar opposite) classes - those who are working poor, and the scare factor of public transit and hassle of traffic is something they just have to deal with, or quite wealthy - and they can afford drivers and/or private schools.
The public school system in SF is also notoriously terrible to deal with, even by US big city standards, as ‘equity’ changes results in bussing kids all over town so there are no ‘good’/‘bad’ schools due to demographics. So siblings will often end up in schools on different sides of town, or kids in a school very far from where they live.
The middle class tends to go to the suburbs where things are less crazy and easier to handle, and they get ‘bad’ things like a school where all the neighbors kids also go, and siblings can all be in the same school. And they can buy into a ‘good school district’. Among other things.
Siblings get preference for the same school, so it's pretty unlikely they'd be on different sides of town.
SFUSD has tons of problems but you are not accurate in your description of what they are.
The real problem is that the kids of parents who can't drive them to school end up having to go to a local school anyway, so the egalitarian idea of having kids go to any school did not actually work out as a positive for anybody but kids who were already privileged enough to have someone drive them to school.
School bus routes have been decimated in much of the country, creating long winding routes with horrible wake up times for children. And a school bus doesn’t take you to any place outside of school and the home.
Growing up as a school child in New York with a transit pass, it was nice to hang out with friends, or go to a museum, or head to a new park, or try a new restaurant, or any number of things without having to involve parents for transport. And I went to a pretty good public school.
this is much safer/practical in suburban environments. do you really believe public transport, in SF, is as safe for a kid?
e: md fix