Geez, its not like we don't have fish and chips here, its just that they aren't their own little fish and chips shops - we don't eat enough of it to justify I guess. In my town, the pizza/sub places also do fish & chips and seafood and many of the general "american" restaurants offer it too.
In New England, Seafood is such a big thing and its so much more than fish & chips, a fish & chips shop wouldn't do very well if they didn't offer fried clams, scallops and lobster rolls and chowda, etc.
I'm in Maine so it sounds very similiar to where you are, plenty of fish & chips, heck I just had some the other day (haddock) :. That said, the places that sell fish & chips do sell other things, I suspect it would be hard to only sell fish & chips with nothing else.