I rather think the simple truth is that some cuisines appeal to many more people than others.

While surely every country and culture offers some tasty dishes I think there is a reason we see so many Italian, Thai and Japanese restaurants everywhere and so few German, Phillipine or Peruvian restaurants.

I am German myself and I am sure you can find more Italian than native restaurants in Germany, simply because it makes for a better dining experience. Not everything needs to be socially constructed.