Walmart doesn't go in blind, they are in the business of extraction. Typically they look to setup a regional store in an area where towns already have optometrists, florists, sporting goods stores, grocers, bakers, homegoods, electronics, hardware, autoparts, the entire town basically. What happens if they didn't come in the first place is life continues in a more decentralized and localized manner, and less of the taxable profit is carted out of the county. Presumably these optometrists and sporting goods store owners of the past paid their income and property taxes from their salaries locally in the area.