I suspect most of us on here, especially those over say 30 years old, walked to school more often than being driven? My primary school was 'local', which meant it was about half a mile away. By the time I'd called round for a couple of friends and we'd taken the long route to stare in the newt pond and then gone via the tuck shop with our tuppence for sweets - well we'd probably walked, skipped and jogged a mile more than we needed to and enjoyed every minute of it. I don't recall any overweight, asthmatic or seriously disruptive children at school with me. Maybe I lived an idyllic life in a 'safe' area or maybe I have long term memory problems, but I'm all for an extra bit of exercise for youngsters however it has to be delivered.
You don't need a trail shoe for those distances / terrains. Nimbus is a neutral shoe so won't have corrected your pronation but also won't have made it worse if that is your normal strike pattern. You could try an inner sole in the Nimbus before splashing out on new shoes.
Bottom line... If you're going to pay good money for good shoes - go to a good shop for good advice.