It's more about what the Chinese market offers (or doesn't) than NRT duty-free being competitive. Having travelled with my chinese colleagues in the past and seen their shopping habits, for the most part goods available overseas are not only cheaper than in China (even if they are buying it from the most expensive location in that country), but more importantly, far more trusted to be a genuine and quality product. Even imported goods sold in China is not always properly stored (unreliable cold chain), or sometimes expired.