I love this argument about 'the best' as the OP is most likely asking fellow Americans, in a similar socioeconomic, age and lifestyle group about their judgment of American v. every other country's food.

Ask this of similar Americans who reside in different parts of the country or who lead a different lifestyle (e.g. 9-5er v. road warrior v. homebody v. party animal v. retired person v. student v. farmer; you get the idea) and you will get all kinds of answers.

Just because you (or I) like something, or if lots of us like it, that does not make it 'the best', only the most popular.

If you believe that the food that you are consuming is, overall, of a higher quality than every single country in the world, bully for you.

I think asking this questions to business travellers who happen to dine in some great cities and restaurants as well as sampling local street cuisine, is hilarious!

Thanks!

(I'd rather continue my on/off travel around the world and sample life and cuisine - one of life's pleasures for me.
My world's best could even include some American food, but I couldn't agree with your hypothesis USA Foodie#1!, unless it's specific to a few dishes, where I've not had better elsewhere!)

I know it's probably not worth your while, but it might be worth considering which major, developed western countries have also had large migrant inflows, before declaring the US the one true source of multiculturalism and dining!