He still ran the numbers.
I was too young to fully understand but basically accounting for every cost it was cheaper to call a cab or rent a car for every situation that actually requires a private vehicle, plus it saved loads of time overall (repairs, maintenance, checks, cleaning...) and headaches in general.
The discussion stuck to me, and I'm always amazed at how it became a realization for so many people decades after.
Granted, this was Western Europe where public transit is ages ahead of most of the US.