Traditional Chinese narratives identify the Zhou Dynasty as the rhetorical "Golden Age" of what they perceive as Chinese civilization. The Song, while certainly regarded favorably as a time of expanding economic prosperity, does not enjoy such status. If Western History in the modern era may be described as being conceived of as teleological (progressing in an upward, positive fashion) then traditional Chinese conceptions might be said to have been the opposite. That is, it was believed that Chinese civilization reached its zenith during the Zhou, and that all subsequent incarnations of Chinese statecraft/culture failed to measure up, though they did try.

Or at least, such was a popular view among many prominent Han Chinese literati spanning the past two thousand years. This answer I've given almost certainly errs in being overly simplified, but it's generally valid (I believe) and should hopefully give you some satisfying food for thought.