Not that long ago, when mankind was more connected to the land and to his place in the world, local food was a truly unique part of each community's culture. New ingredients might be introduced and new food traditions developed but in general, each region of the world had recipes and a food culture as unique as the languages they spoke
food has always been an important part of one's identity. like learning your mother tongue, children learn to eat and like the foods of their society. people celebrate and take pride in their local recipes and food traditions.
even as people move across the world, they take their recipes with them. you can get great indian food in london and japanese immigrants have created a whole subsection of peruvian cuisine
unlike some other elements of society though, food culture has always been very flexible.
incorporating new elements is normal, whether that be new ingredients or new ways of cooking.
irish food without potatoes seems impossible but the rather new ingredient was actually incorporated into many older irish recipes rather than just replacing part of the food culture completely.