Pizzas in the US are pretty huge - they’re not like a classic pizza for one person as in Italy. I think a two-pizza team is up to about sixteen people.
Two large pizzas feed three to four people if they're all under 30.
I'd say 2 pizzas for 6-8 people is totally fine assumption.
When Americans order a pizza, it's typically for a party of 8 people?
That's logic, that is.
Yes, it's a tourist trap meal. We here in Chicago really do like deep-dish pizza, but many of the more famous brands exaggerate the thickness because it seems as though tourists prefer it that way. A typical Chicago resident isn't going to buy one like this more than once every few years, unless they have visitors that insist on it.
You eat it with a fork and knife. Despite the huge amount of cheese and sauce, a good one will have a really crunchy crust and it should be so good that you consider it one of the best parts of the pizza.
The flavor/preparation/ingredients are what make a good Chicago-style pizza and not the thickness. In more residential areas, you'll have pizza shops where the deep dish pizza is no more than 1 inch, which is really what a Chicago resident buys for themselves (but the thin crust is most definitely purchased more frequently).
I think you did the math wrong?
Area is pi x r^2, which for a 16" pizza would be pi x 8^2 = pi x 64, which is right about 200in^2
A few of the pizza places around here offer 20" pizzas, which would be pi x 10^2, or pi x 100 = 314in^2, which is actually big enough to feed a couple people.
That said, whenever I read "two-pizza team" (a term I've never heard before), I assume that means 4-5 people at most.
And a 2 pizza team is the number of people you can feed lunch to with 2 pizzas.
Most people would do 1-2 large slices for a lunch, so 4-8 maybe 10 people is a 2 pizza team.
About the same size range as a rifle squad.
Almost all the by-the-slice places I've been to take slices from their large or extra-large pies. The only exception I can think of would be Pinup Pizza on the Las Vegas strip (30 inch diameter pie).