One size fits all
We pretty much all know that the real answer to questions of the sort "why does X occur"? is "to get the girl".
You know what I mean right? "why do birds grow elaborate feathers?", "why do rams butt heads at 30 mph?" Why do boys play football?", "why do bloggers blog?".
Now, LeBron informs us that this simple, powerful answer also applies to explaining our current global imbalances, viz:
Q: Why do the Chinese save so much?
A: To get the girl!