I find someone who would claim that only immigrants can't produce decent restaurants to be actually quite strange. America is full of great restaurants started, owned, and operated by Americans. I suppose you could only like Ethiopian food, or have some strange preferences, but the vast majority of people in the world consider many. many US restaurants to be good. Maybe I am misunderstanding you.

Burgers and soul food, and the classic American interpretation of Italian food, are very popular at the low end. I see my governor occasionally at the French laundry, and Thomas Keller is American as the come (from Florida). Napa is hardly an "immigrant area" whatever that means. Alinea is also fine, but I was allergic to something the last time I ate there. Grant Achatz is American (from Michigan).

I think you are just plain anti-American, and that is not that unusual, but when extended to American food, becomes actually quite surprising.