Seems to reflect demographics as well as generations tbh.
California and Texas are the most populated states in the country and Mexican/Tex Mex is king out that way while the Italian food is "average at best."
Also, the Southeast has terrible Italian food outside NOLA while the Mexican can still be pretty decent(I've had surprisingly good Mexican in the Carolinas).
Outside parts of the Northeast and Chicago, Italian food isn't really done justice in America whereas Mexican food is more consistent here.