As for the parent comment, I think he's alluding that pre-modern Japanese art and culture had a lot more overlap with pre-modern China's, which makes it somewhat less notable from a Chinese perspective (e.g. something like England vs Australia; different, but there's overlap).
But post WWII we see a massive divergence in cultural export and exchange (e.g. England or Australia vs the US). South Korea is another example (I've actually seen Japanese entertainment consortiums lamenting at the perception that the S. Korean entertainment industry seemed to be better funded and more able to export their culture). Just looking at Chinese history, the golden age of creativity and inventions seemed to occur when there were more freedoms (which I would argue is pretty much any era prior to the PRC since their control is unprecedented in conjunction with modern technology). Granted it was the olden times, so there were more things to be discovered, but it seemed like China back in the day was on a roll (off the top of my head, movable type, paper, matcha, bonsai, porcelain, celadon, silk, gunpowder)
