Having to walk limits your employment opportunities, particularly if you're not able to just pick up your life and move homes. It also limits which stores and other businesses you're able to reach; less competition means you end up paying more for goods and services. If you're a yuppy living this lifestyle by choice, able to change apartments on a whim and rent a car whenever you need to go to costco and able to shrug off higher prices in local shops anyway, then it's all good. But for the average member of the working class, quite possibly with a mortgage and kids in school, being forced into this kind of rootless urban pedestrian lifestyle is a raw deal.