Could just be that Scandinavians and the Celts/English (I'm half Norwegian and the rest Welsh/Scots/Irish, BTW) had potatoes as a staple long before they got exposed to corn.
All of my grandparents figured that corn (outside of novelties like popcorn and sweet corn) was best used for drinkin' and feed for the cattle...which were then served up as their Meat-and-Potatoes daily meal.
Breakfast? Bacon and eggs or oatmeal.
Irish = Potatoes.
I think you’re exactly right. As far as Scandinavians go, I think there were far fewer compared to the Irish, and mostly immigrated to Wisconsin, Minnesota and the Dakotas.