My thoughts are that the population of the US is circa 350...

My thoughts are that the population of the US is circa 350 million. Most are very heavy consumers of manufactured goods compared to any other country. China has the largest manufacturing industry in the world by a significant margin.

Therefore I see China needing the US probably more than the vice versa case. However the Chinese are arguably the most astute business people of all, easily surpassing the Americans.

A simple but overwhelming example is the following: 

America spends $ billions and maybe even $ trillions fighting wars overseas and has done so since the second world war. China might spend a lot on defense but wastes little money overseas fighting futile wars that don't achieve a great deal in the end.

OK I will concede that fighting wars supports the armaments industries at home, but in the final analysis that is not enough justification economically. The military aircraft and arms industries would do well enough just selling to other countries especially the oil rich gulf states.

And secondly:

The US hands out free money to so many countries and to organizations such as the UN, Climate Change Agencies, for what?

They are all highly corrupted and the bulk of the money ends up in Swiss Bank accounts in the hands of a small number of individuals.

The late Yassar Arafat had a wife in Paris living like the Royal family and about US$3 billion in his personal bank account that we know about.

China does not hand out free money, gives little to the above mentioned agencies if at all, so wastage of funds is minimal.

Instead China finds poor countries that do need aid, and buys influence and loyalty from them in the UN voting and in other ways. The aid is provided but definitely not as free money. China takes a stake in the country's infrastructure, or even better, a stake in a valuable resource such as gold mines, other minerals, forestry etc.

You now tell me who is the smarter. The Chinese need the US but play the game as if the US needs to come to them cap in hand and all humble.