Because the Earth is a sphere there's a lot less land between 70 and 80 degrees latitude than between 0 and 10. Quite apart from the difficulty in moving people.
Surely you are joking. Japan is not self-sufficient with respect to food; they have to import around 63% currently and it is of great concern to them, see https://www.japantimes.co.jp/opinion/2019/08/20/editorials/j... .