Flip side for me: I'm from Michigan, not the Detroit area but a mid size city (Lansing) and we have a huge variety of food, albeit not a lot of choice inside some of those varieties.

I had the profoundly weird experience when visiting San Francisco of being with some people who were excited to try the new food they had never heard of called "pierogi" that a place had opened up to sell nearby.
It was perfectly good and I was delighted to be able to tell them that they in fact did want onions in their food, but it was real weird watching them get excited to try what I consider grandparent food. (It's a food your grandparents give you, or you make a bunch of and freeze)

I think there's a thing where certain ethnic groups "big migration wave" came too early for them to reach big populations super far west.