I am reminded of a company I used to work closely with. It had once had 50% of the global market for its particular market niche. It spent a lot on market development; because of the commodity nature of the product, brand differentiation and thus brand loyalty was almost impossible. Thus the other small fry who added up to the other 50% got a free ride, but it was still worth it, because the expansion of the market paid for the expense.
Over time, and a couple of recessions, however, the market leader's share fell to 25-30%, partly because of the complacency that comes with success. It was no longer worth spending money where 75% of the benefit leaked elsewhere. After a perception lag, the market development activity was axed completely. Of course a co-operative programme between all the producers could have plugged the gap, but trust levels were low (not to mention anti-trust issues) so nothing much happened. Everyone was worse off, but the market leader was
relatively better off.
If China moves beyond a tolerable level of economic bullying and crony regime support, then an obvious reaction would be to form an encircling anti-Chinese alliance of Japan-S.Korea- Vietnam-India, perhaps Russia as well. But that is more unstable and dangerous, as well as eliminating the free ride for the participants. Indeed the current status quo is safer for China - cold wars are polarising, and distract from making money. Indeed it would be in China's interests to quietly bribe the US to stay - perhaps the bribe could be in the form of buying useless American treasury bonds?
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But yes, there is no point in the US staying in Europe, especially as it reinforces the US' ME obsession. The latter, and ignoring China, reminds of fractious European powers ignoring the elephant across the Pond.
Pessimism is the soft option.