the "patriotic vegetable" staple in China - why was it cabbage and not potato?

here http://www.taipeitimes.com/News/world/archives/2003/11/06/2003074784 is an example of article talking about how back in bad not-so-old days the Chinese heavily relied on cabbage. Why cabbage? Europe, America and Russia have for the last couple of centuries heavily relied on potatoes, and cabbage was not, AFAIK, considered a significant source of calories. So why couldn’t Mao’s China grow potatoes just like us?

My WAG is that in this context, “vegetable” is a separate category from rice and potatoes. I know at least in Japan there’s a fairly clear culinary distinction between a starch/carbohydrate item (rice, noodle, bread, potatoes, etc) and a vegetable item (any edible plant that isn’t primarily carbs).

Potatoes are an imperialist plot! I think I might be serious.

In many parts of the world, potatoes are the cheapest source of calories, but cabbage is the cheapest source of most of the other nutrients you need. Cabbage is indeed a staple in most of Europe as well as Asia.

I can’t speak for anyone else, but when my Chinese wife talks about vegetables, she’s generally referring to one of a hundred different kinds of leafy green vegetable and not corn, carrots, potatoes, etc.