Taco Bell is about as "Mexican" as the "Mexican" Restaurants, I would say the food quality is about on par, Taco Bell has a drive thru and there are no utensils or plates required.
But, while I would agree we don't exactly have diversity, it's what the public wants. Any business plan includes a survey of the potential market. You have to have a potential customer base that will support your business. More people are going to go to a "Chinese" buffet than PF Chang. It's why we got an Aldi's and not some upscale food store. Walmart and not Nordstrom. It's not like Annapolis, build it and they will come. You build anything in Southern Maryland and you are asking people to pass an existing outlet.