Its reached a plateau technologically, there isn't much else they can do to excite consumers to entice them to replace what they already have, and most people have a phone as well.

Chinese people also have a higher rate of fixing things when they break and they have specialist repair shops everywhere that can replace any component of the phone, so its a different market.

You can't just look at a market and say "oh, its going down for no reason whatsoever" there is always a reason. Its just a question whether the lack of growth will cause a crash in the overall market now.