An Argument on the View of the "Piled-up Poverty and Weakness" of the Song Dynasty

Since Qian Mu introduced the view of the piled-up poverty and weakness of the Song Dynasty, almost everyone takes it as the basic characteristic of the dynasty, but it was not true of the fact. The Song Dynasty was smaller than the Tang dynasty in territory but more prosperous than it in economy and richer than it in financial income. Three of the four world-known inventions by the Chinese were made in the Song Dynasty. Compared with any former dynasty, the Song Dynasty was by no means poor, or rather, it was a little richer. In terms of military offensive strength, the Song Dynasty was a bit weaker than the Liao and the Jin Dynasty but in terms of defensive strength, the Song was a bit stronger. If compared with the Western Xia Dynasty, the Song's offensive strength was a bit stronger. Mongolia was the strongest empire all over the world in those days, but it was only the Song Dynasty that was able to rival with it for quite a few decades. Thus, the Song Dynasty could be taken as one of the strongest throughout the world. As far as comprehensive national resources are concerned, the Song didn't rank among the weak but among the strong powers. In comparison with the East Jin Dynasty, the Song Dynasty had a territory almost as big as the former, but much more economically developed than the former. Then, why was the former not labelled as the piled-up poverty and weakness but the latter? This is obviously unfair.