See, now why is this the case? If you could just chalk it up to unfamiliarity, well, is that a human species thing? Because Eastern literature, particularly that of Japan, takes a LOT of western folklore and myth and incorporates it.
Or maybe that's just what I've seen because the westerners will import stuff that's easier to take.
I think the third variation on what you're saying is that we DO get the influence of non-western culture, but we just don't recognize it. (maybe that's what you said but I just didn't understand you correctly). For example, the Magnificent Seven. How many non-Kurosawa fans knew it was based on his flick "Seven Samurai?" Just throwing out some thoughts. I don't have it all organized yet, but one more:
Multi-culturalism is a relatively new thing in the West. We still aren't used to it. But most non-western cultures have been in Colonial situations in the last couple hundred years: Africa, India, Japan, China... and have had another culture forced on them. That's why we hesitate to do it, because while these non-western cultures are used to colonial powers, using non-native mythology ocmes easier to them. While we think we're becoming "mature" by making an effort to incorporate non-western elements.
I actually have a really cool serial fiction or comic planned relying heavily on some Buddhist and Chinese religious concepts. I just need an artist or a forum for the fiction (I'd prefer comic for this one).