actually, those interested in regional differences in cuisine would
find more variety in the US; not just because of geography influencing
native ingredients, etc. but because of the varying cultures of the
immigrants.

Friends,
As someone who lives in Queens County, New York (NYC)--the
immigration capital of North America (or is it the World?), I would
have to agree with this,
I can find almost any ingredient, spice, vegetable, sauce, or food
stuff that I can imagine if I look hard enough for it. This is due to
the immigrants that flock into NYC from all of the
prefectures/provinces of China and Taiwan/Hong Kong/Tibet (please no
politics here!).
The simple truth is the immigrants come to a city, set up the supply
lines from the old country, and everyone enjoys in the bounty.