Ryu Murakami is far more popular in Japan. I think knowledge of Haruki is more a reaction to his popularity in the west.
Although his first book, I believe, did quite well in Japan when it was first published.
Someone said he writes in a way that is easily translated. But he's also said that rehearsing is important when it comes to English language speeches because he lacks the grasp of English (not necessarily vocabulary) to pick the right words on the fly from a sea of options. Whereas his job is twisting and manipulating and mastering written Japanese. So I think he is comfortable in Japanese in that way.
His references, subject matter and philosophy is just not particularly Japanese.