I understand you plan to include bikes on the roads themselves. But making a city less dense and filling it with parking spaces for automobiles makes the city hostile to all except automobiles.
> * Zero-emission vehicles
Zero tailpipe emissions. EVs still emit 1/2 as much lifetime GHG as a combustion engine personal vehicle [0]. Your plan would make your theoretical town less walkable and bikeable and force former cyclists and pedestrians to drive EVs. This results in net higher emissions since more motor vehicles would be on the road.
> Traveling out of the big city or to orthogonally to the main public transportation routes, or with small kids, or with large luggage, with a week worth of shopping bags, or when I have to get rid of garbage...
These are valid use cases but they do not justify increasing a town's emissions in the middle of a climate crisis.
> In order to get there, we will have to reduce the amount of apartments per sqkm and even more so the amount of office space and shops. This will work in two ways: It will naturally reduce traffic and free space for car parks.
This would make the city less economically productive per sq km. Compare the tax revenue from 10 parking spaces in a parking lot versus mixed use row houses & businesses in the same lot. Plus people can actually live in the latter. Is there a housing shortage in your city? There sure is one in mine. And it has tons of tax subsidized parking :)
[0] point #4 in https://www.epa.gov/greenvehicles/electric-vehicle-myths