My guess for the restaurants would be that most of them cater to the higher end market. You have all the apartments, which based on my coworkers, I'm going to go ahead and assume are filled with primarily young professionals starting out. They can't afford to eat at a Waters or Tillmans every night, or even once a week.
That leaves the restaurants relying on people coming in to support them and keep them going. With the restaurants that are there, my wife and I go out to eat in W7th, maybe once every couple of months, and we don't bring our kid.
The rent is probably too high for it, but I would love to see some new restaurants that cater to the middle of the road crowd that isn't a taco place. I would bet something that is in the price range of a Chili's would do well.
I would love to be able to go to a new mom and pop restaurant that focuses on doing decent food at a reasonable price. Maybe that price range is only available to chain's due to scale.