We see a lot of these wannabe-oracles out there. They have to make bold, emphatic predictions otherwise nobody cares or listens. The fact that most of them end up wrong is irrelevant because those get ignored and forgotten after the fact. A blind squirrel eventually finds a nut, however, so when someone like this finally does have one of their predictions turn out correct, the non-critical thinkers will dig it up from years ago and be shocked and amazed by how much of a genius he was all along. Those 99% of other times he was wrong? Irrelevant.
That being said, China does have a lot of problems they'll need to deal with over the next decades. Like the Japanese before them, there are costs associated with rapidly modernizing and globalizing your economy, and China has not yet paid.