World trade is already centred upon China. China pays the best price for most commodities and sells manufactured goods at the best price. Thus most, if not all, nations need to trade with China or suffer economic disadvantage. The value of US Treasury bonds is presumed upon the liquidity of USD financial markets, the universal acceptance of USD and the credibility of the US government honouring the debt obligation those bonds are. It is no secret that the US government has been operating a chronic deficit for decades and consuming more than it produces - this enabled by the global reserve currency status of the USD enabled by the hegemony of the SWIFT trade payments network. The viability of this continuing is highly questionable and increasingly in doubt- this is part of the reasoning given by Trump for his imposition of global tariffs. In current world circumstance if the US and its Treasury bonds were to default there would be massive dislocation and losses on financial markets, but trade in the goods people need and want would continue and be denominated in different currencies as is already increasingly the case. The USD based financial markets could well fall apart leaving huge disruption and wealth redistribution- but actual trade in commodities and manufactured goods would not cease. It would shift substantially from current patterns and protocols to new patterns and protocols. The US era of empire would be over.