I could see the pork knuckles actually supporting that fact since I associate them with being what people eat when they cannot afford "conventional" cuts of meat. (I realize this is probably somewhat a cultural bias on my part as well. For example, I recently learned that Chinese style pig's feet are delicious).

I know in Cincinnati (which has a very strong German influence) one of the signature foods is goetta which is a sausage stuffed with steel cut oats. I wonder if some other German dishes that we think of as indicating heavy meat consumption could actually have been ways of stretching out the available meat.