I personally believe the reason for non-western fiction gaining so much mainstream traction is quite simple: it provides a perspective almost entirely seperated from the reality most people face. Even simple scenarios, like running a small store or living life in a rural village, are so different from our usual experiences that it provides a way for our brains to release some of the pressure that comes from our busy day-to-day lives. The "isekai" genre (being transported to a different world, usually after dying an unfortune death) is an extreme take on this, where almost all connection to reality is removed entirely.

Compare those stories to most (not all) modern mainstream western fiction, and you'll find that a lot of it tends to take place within our existing world instead.