Here's a statement that's obviously true:
"China is still comparatively poor. Therefore, it has a lot of growth potential, and can keep growing fast for decades to come."
From a macro point of view, that's surely not wrong.
However, we need to remember that some sectors of China's economy are already much larger than elsewhere:
China has 19 % of the world's population and produces roughly 5 % of the world's GDP (at market-prices; closer to 10 % based on PPP).
But according to this article, China will account for 60 % of the world's 2009 iron ore purchases.
And according to this paper, China produced 35 % of the world's steel and 27 % of the world's aluminum as of 2006 (nearly all of it for domestic use). Both percentages have increased further since then.
Seems to me that China's growth potential in these sectors will be rather limited...
(Just another way of once again stating the obvious: China needs to rebalance its economy.)