for first, most people do not own cars and do everything via public transport/bicycle.
plus. it is often faster to use public transport than using a car, and cheaper...
supermarkets, grocery stores, hospitals, offices, appartments have generally no or little parking spots.
you will have to find dedicated parking spots which are pretty expensive, and will in fine have you walk around as if you were going to the station...
oh and yes, as i mentioned before lots of apartments don't have parking spots, so you will have to walk some to get to your car, and you will have to pay a hefty sum to rent the parking spot.
there are dentists/hairdressers/grocery stores/restaurants pretty much everywhere in tokyo. use google maps and try by yourself you will see.
people haul their stuff by hand or with their bikes.
people who don't have a very specific reason to own cars simply don't... there is no point. the building where i live has way less car parking spots than units (and it is illegal to own a car without a dedicated parking spot in japan).
people who have cars are generally one of:
- do not actually live in tokyo
- go in and out of tokyo often
- need for work (cargo)
- hobby / family need (haul a lot of stuff regularly or enjoy driving)
i'm specifically talking of tokyo, outside of tokyo you will find lots of parking spots and cars.