In a car you can listen to podcasts or audiobooks at least. If it self drives for you then email and slack is fair game too. 3 separate trips wouldnt be hard to imagine. The commute is trip one. Picking up takeout is trip two. Running to target after dinner is trip three. That sort of thing is tough with transit though. Oftentimes your business is not in the same place, so you might be going all over town running errands or making appointments. The car is of course much faster to pivot between places than tranfers and waiting. Walking is good, but clearly people today have opted for the temporal convenience of driving over the physical benefits of walking, which might be faster to achieve with a more intense gym session. Its not like many rail stations see 100% car free living within their walksheds today. For some they have big lots because many of their riders prefer a few minutes driving to the station in a climate controlled vehicle over the alternative.