And yes it is hard to attribute something to one "person" because most things are made from pre-existing components (without electricity, no tv) I dont think anyone would say they invented the telephone.
I think I might prefer the US ones though. Better dough to topping ratio. Sometimes it feels like I am just eating a whole lot of dough.. Though the NY style ones I have had Wére extreeemly greasy though, and incredibly salt (like your monthly intake lol, I am a salt lover, but they were just barely within the limits of being edible..). Not sure if that is a common thing or just from the NY pizza delivery. I have a feeling the greasy thing is (going by what I see on tv) but the saltiness might not be the common thing.
The innovations in New York were making a pie with a semi-rigid (you call it floppy, but try eating he ones in Naples they are barely cooked there) crust cooked golden brown, cut into triangles, with sauce, cheese and toppings distributed and spread evenly over the whole pie, such that you could take one slice and easily consume it while holding it in your hand or on a paper plate. Nearly every single pizza I have ever ordered in my life, be it in Seoul, Manila, Riyadh, Tel Aviv, Athens, Moscow, London, Rome, Bangkok, Miami, or Los Angeles have all fit this description. There are a couple of exceptions to this rule.
2. Chicago-style pizza which I've had in Chicago and elsewhere which is really more like a quiche. Made with a deep-dish cornmeal crust.
3. this one place I used to order from in Croatia where they didn't cut the pie, but in all other ways was still much more similar to New York pizza than Naples pizza.
and a few pies here and there that were square-cut... but still cut