Frankly, I cannot see why anyone would want to spend half their time sitting in traffic jams but meh.
Because it's not just about going into cities. It's about getting to the city too. It's about where the people who have ended up in the cities have started their journey.
I spend my days going into semi-central locations, mostly retail parks. To get there I inevitably use the motorways, which are inevitably rammed at 8am and 4.30pm on my way home.
So my first argument is, I could not do that on public transport. My nearest railway station is 14 miles away, which takes 1hr10 on a bus because it goes everywhere on the way, because that way they can limit the number of buses they run to cover the areas that need a bus service. Then I'm on a train and will have the same problem the other end, because trains don't go anywhere useful any more - they dump you in a big city. So it's trains plus buses which means loads of time.
Second argument is, that in my car in a traffic jam it's my space - I'm not getting irritated by people on the phone, or smelly people, or hearing the tssh-tssh-tssh of someone's headphones. Yet I can listen to music, talk on the phone or fart whenever I want.
London is perhaps the exception with a genuinely good tube service, but in other cities if you banned the car you'd have no other good way of getting into the city. We need the trams and trains to be useful first, and THEN we can consider getting rid of personal wheeled bubbles.