Well, let’s see. I think it would depend on who their clientele is, which probably has to do with their geographic location.
Why would a restaurant in San Francisco cater solely to the palate of Indians? They are catering to a diverse population in that geographic area, they want to make food that could be enjoyed by as many people as possible.
It’s the same with every other ‘ethnic’ food. They do not really eat burritos like we do in Mexico, for example.