I remember how exceptional the public transportation is, in and around Tokyo. You're lucky in that regard! And I remember how difficult it was to get anywhere by car, too.
Unfortunately there's really no option to driving a car here. Everything is spread out, and we don't have the small 'mom and pop' type stores close by. There is no public transportation to speak of, and it seems like it's 95 degrees Fahrenheit, with 90% humidity all the time, too, so walking isn't practical (even if things were close by).
Once you get out of the 2-3 cities in the country where public transportation is effective (NY, Chicago, DC, etc) the U.S. is definitely a car culture.
Yup. I bragged about not owning anything more powerful than a bicycle when I was in the Bay Area in California, but now that I'm out in the boonies, motorized transportation became a necessity.