>Why can't China now run a huge deficit like the US is expected / encouraged to do, thus becoming consumers of products built in the US and Europe, instead of the other way around?

Because banks and other Govenments believe that there is a ~20% chance that China will implode and have a popular revolution over the next decade for any given decade. That's Morgan Stanley's number, other banks may project different numbers. China is incredibly unstable relative to the US and European countries. Half of China, does not want to be part of China, and not in a joking, "Texas will secede" type of way. There's tons of poverty, not enough water, overpopulation. There's little democratic self correcting mechanisms.