Growing up, my dad had a truck, mom had a car. They both worked full-time. Brothers, when they got old enough, each had one (as did I when I hit 16). When I got married the first time, I had a car and a truck, the wife had a car. Four years later, after joining the military, that went to and stayed at 1 vehicle for the family until 1990, when we needed the two for our busy and diverse schedules.
Went to one again in '93, two after getting married again in '98, but back to one by '99.
Now:
I don't own one, or have a wife. My sister, her husband, and each of the two oldest daughters (one lives with us) has a car. They get groceries, and seem to invent errands so they can drive more. I still bring home the odd grocery items in bags on the bar, and drive one of their vehicles about 2x/year.
Last summer, when I was trying to get some boxes to clean up crap in the back yard (bike boxes from work were good for it), I'd get 6-7 in the small trailer, haul them home, and get 40 lbs. of branches and debris in each box. Three weekends was all it took. (Big yard.)
With gas prices, the one daughter doesn't drive much; my sister and her hubby seem to play 'gas-pump lotto' for who gets the gas tank fed. I just shake my head and keep pedaling......
At least HE has stopped crabbing at me about riding all the time, and calling me "Lance Armstrong". (Sister would ride a LOT more if her bike was up and rolling.)