But some people think they need their car because they think they need to move a lot of stuff regularly, for instance between their home and their parents, and their parents don't leave in a place easily reachable without a car. This stuff can include pets, like cats. I think some of these people could do things differently, but maybe some of these people might genuinely have these needs.
Going to work daily to a place that needs a car is another concern. Sometimes at times outside the public transport hours. Very good public transport could mitigate this. But some people might also need to move a lot of stuff (tools, materials) for work, which might be complicated with public transports.
And when you move, public transports won't cut it.
But we could have almost car-free cities that allow these specific cases (possibly with special authorization), addressing most people / most cases with good public transport.