It's very simple actually. For instance, let's assume Walmart automotive takes maybe 2-3 FT employees to operate, where this may normally be fragmented across 2-3 local mechanics employing 3-6 FT employees each. Then of course you have the 2-3 local services which catered to them (E.g. cleaning services, real estate agents, CPAs, ect). Then, multiply this for each Walmart department (Electronics, Groceries, Pharmacy, Auto, Household, ect.) and there's your town.

What jobs? Rural and suburban communities not linked to an urban area have less and less every year. The cities are growing and towns are dying: there are very few new jobs, much less “more productive” ones.

Think on it for a second: if you could work a better job than small grocery store employee, wouldn’t you have already? Why would you wait on walmart to exist?