@BethanyBlack I think it because there was simply so much immigration. Immigrant stories are more recent and powerful. My husband's family has immigrants and natitive New Mexican roots, so culturally New Mexico and Mexico is very strong, talked about and obvious.
By contrast I am mostly American English. My earliest ancestor came over in 1688. The most recent immigrant I could find was Irish and came over in 1792. Scottish. Welsh. Maybe French Huguenot. We don't have the same strong cultural traditions, like making tamales after Thanksgiving.