Part of it is that America just has an insane amount of resource richness even compared to historical empires of it's comparative influence.

Let me try to explain it in agricultural terms. America is a nation of immigrants, and yet a common phenomenon is an observed disconnect between what Americans consider local cuisine from a given country and what people from that country today consider average cuisine of their culture.

This is because those immigrants were the tired, the poor, the hungry masses yearning to be free. The cuisine they brought was the stuff people would make to subsist as peasants, notice how many different varieties of "take this basic grain as a filler then layer on bitsins and fixins to give it flavor and nutrition." Meanwhile in the home country, cuisine culture continued to be defined by the elites who had already been defining it. What's really interesting is that the cuisine brought by the poor, did not stay pauper meals.

This is because America as a country is so packed to the gills with farmable land that ingredients considered a rarity for sheer cost in "the old country" were abundant to the point of being cheap. American serving sizes are so big because they were pioneered by people who were thanking god that they could be that big. Chop Sui literally was just "whatever you can throw in the pot, serve it up!", tacos and sandwiches were invented basically to maximize the flavor and nutrition of expensive fresh ingredients on limited supply, Pizza has roots as the equivalent of a street pretzel in NYC.

Imagine if someone took the NYC pretzel, moved to a land of unheard-of plenty unseen by human eyes thus far, and decided to spice that pittily ass bread and salt with choice of topping by loading that shit with the most unimaginably luxurious ingredients they could conceive of because that shit is all cheap there. That's the story of Pizza. That's what happened to basically every peasant food culture that made contact with the US and its because American resource richness is just that unprecedented for anyone who isn't from America already to conceive of.

Stalin once stated that WWII was won with, "British Intelligence, American Steel, and Soviet Blood.", but America wasn't just a factory for the world, the American kitchen put into that war just as hard as the American foundry, arguably more, America's first casualties of the war were the merchant marines who faced U-Boats head on to run food aid to the British public and anywhere else they could slip past the Nazis.

We got so much shit we will literally give it to you for free sometimes

That is how 4% of the world population ends up sitting on 25% of its GDP