Many of these traditions include "new world" ingredients such as tomatoes, potatoes, bell peppers, corn, squash, some beans, &c that wouldn't become common in europe or asia until the 16th or 17th century. While still older than the founding of the united states, they're still "newer" than many people realize. These new ingredients were incorporated into older traditions just as new ingredients will be. Noöne will force it on anyone, but people will experiment and find culinary and economic reasons to use new ingredients.