China's manufacturing has always been about providing cheap...

China's manufacturing has always been about providing cheap products to mass markets. Reduced single item profits are irrelevant when those small profits are multiplied by quantities sold. Tarrifs in the US or Australia are relatively insignificant compared to the global sales it's capable of and gets.

Absolutely it's sustainable for them, they have almost 1 in 5 people globally working towards the same goal. Not the west as we need share holder returns to drive investments, no returns, no investments and 4 out of 5 people globally working towards individual interests. The scales are on their side.

note. Chinese population is close to 18% of the world, the US has ~5%, India ~ 18%, Russia ~ 2%, Australia 0.3% (https://www.worldometers.info/world-population/population-by-country/)