This caveat destroys the rest of your points, as logical as they may seem.
Remember the original argument was "I think public transit will continue to dominate in parts of the world where it currently dominates" I'm taking that and strengthening it to a significant expansion of transit, but obviously not everywhere can do transit.
If the lanes on the road can fill up, you have enough traffic to sustain some busses.
In emptier areas that's a pretty different discussion, but importantly you still wouldn't need to design around cars. Slap in a very basic road and it'll handle all the cars fine.
No one was suggesting that.
> I can carry many items in its trunk, making it worthwhile to make multiple stops on my journey. Public transit is not meeting my use-cases.
Well the guy I was talking to was only worried about one or few trips per month, and we only need most people to use transit for the scenario to work.