The first city has a population of 8M and the second city has a population of 800K... The difference is astonishing... What's even stopping Walmart from entering New York...
Definitely not the case in New York City, Boston, etc. Wal-Mart has never built a store without a sprawling parking lot. It would be ridiculously expensive for a penny pinching store to use 15 acres of land in the most densely packed centers. You'll find them in the suburbs though.