So let's take a different approach: Let's find a better solution for individual transportation that doesn't require human labor (e.g. pedaling) and offers the same benefits (ability to comfortably make 500 km per working day, for example - that's average daily mileage of a taxi driver).
You seem very much in favour of cars, but also imagining that cities without cars would look much like cities with cars. Huge amounts of land are given over to roads and parking. Get rid of these and you have much denser cities without decreasing usable space per inhabitant.
But if you make cities even densier, you'll have to restrict their height. People on the first floor still want sunlight for a reasonable time :) Meanwhile wide streets allow tall buildings..
