In college I didn't have a car so I walked/biked/bussed everywhere. Going to the market was still a hassle and I only had to buy for 1 person. I still had to go often because there was only so much I could bring home in one shot. Now, when I go to the market, I'm buying at least a week's worth of groceries for a family of five. I would need a pretty big bike trailer to get all those goods home. And since it would take quite a bit longer, I'd also probably need to add something to handle the frozen/refrigerated things. So, I bike for leisure and not for utility.