Most of what you've written are arguments for China to be on the up-and-up in the next 10-20 years, not in decline as you seem to think (undeveloped parts = still has areas for future growth).
Others are just on par with the situation in the West (credit debt, propped up etc).
>(I have a good hunch most people that comment favorabily on China here, have never been)
Which doesn't say much. There are tons of people who don't understand anything about their own society despite having been born and raised there (which entails more familiarity than merely living in some place for some years).