I don't think he is deliberately trying to mislead the markets -...

I don't think he is deliberately trying to mislead the markets - though I know he doesn't have a crystal ball - this is just his gut feeling based on his considerable experience though without special knowledge. His idea that the China boom will finish within 10 years means nothing - there may be ten years of great profits riding the wave until then, or it could happen tomorrow.

The problem with such an influential person saying such things is that the comments tend to become self-fulfilling given the weight people put on them. I think it is irresponsible of him to say this unless he has concrete reasons for doing so, and not just a desire to see it so in order that the US retains economic supremacy.

There are too many variables controlling the world markets for anybody to be able to take them all into account or even know what they are. Economists forecast strike rate in predicting change is generally little better than flipping a coin (though of course much more expensive) because of this.

He always paints a pretty picture about the US economy and talks down others. I recall Greenspan saying a couple of years ago how strong the fundamentals of the US economy were and how tentative the Chinese one was - and since that time China has expanded over 20% and US a mere few %.