Can and want to or being efficient are different things. I "can" travel around in a city using public transport with 3 kids and all their sporting equipment, do I want to, no. Would any sane person want to? No.
Unless you're going surfing, 3 kids and their sporting equipment fit in a small hatchback, with room to spare.
If the roads in cities are wide enough in cities for literal trucks, then they're wide enough for your car. Widening roads and making cars bigger makes pretty much everyone less safe.
Don't get me wrong, you're free to live in the boonies and drive 400km to your sports club, but don't call me narrow minded because I can load up 5 people in my VW passat and drive 500km for a 10 day vacation, or because I prefer not to get bulldozed by a car with a higher hood than me while walking to my local sports club.
As a practical example, in the UK, on average a young g child lives 1.7miles away from their school.
That is an easily walkable distance for most children, yet lots of parents choose to drive it because they feel the streets aren’t safe to walk on in rush hour.
If by redesigning streets to make active travel more appealing, you could reduce the number of cars on the school run by 10%; it would improve the traffic situation for the ones who still need to drive. Win-win