what kind of niche cheeses is null into? walmart will only have cheddar, mozzarella, and swiss. all mass produced and with no flavor. a supermarket, such as vons or ralphs, will have more variety, better quality than mass produced but will be limited with cheeses from western europe and italy. these supermarkets also have non processed artisanal breads.
if null wants eastern european cheese, then, yes, you will need to go to the city to buy them. there is no a big enough market anywhere in america to support it. but if you just want variety in cheeses, just drive to a supermarket instead of walmart. they are basically in the same area.