I have a similar theory for restaurants at prime tourist location, the closer it is, the worse the food and service are.

And it kind of makes sense, as:

1) The real state is obviously more expensive, so little money left for the rest

2) The traffic is given, people walk in even if the place is on fire, so no pull is needed

I think a good test for this would be lookin at michelin star restaurants (better than gmaps)