Well, the wikipedia articles on human development and developed nations seem to indicate that to be considered a "developed nation" you have to have good per-capita rates, widespread infrastructure (admittedly, while China has first-rate infrastructure, it is only present in urban centers, to hell with rural areas!), and probably the most critical point re China is that you are into a Post-Industrial economy, with a larger service sector than industrial sector.
As far as my readings and knowledge can tell, the above are indeed points where China fails.
There's a lot of background mess in our mental pictures of the world. We try and be accurate on important issues, but a whole lot of the less important stuff we pick up from the media, the movies, and random impressions. And once these impressions are in our mental pictures, they just don't go away - until we find a fact that causes us to say "huh", and reassess.
Here are three facts that have caused that "huh" in me, recently, and completely rearranged minor parts of my mental map. I'm sharing them here, because that experience is a valuable one.