The trends of the past 15 years are stretched thin amid the growing manias for America and AI, which are supercharged by excessive US stimulus, the gamification of investing and the rise of algorithmic trading and passive money managers.
In truth, part of the reason the US has done better is that we've had a great deal of fiscal stimulus, even though we don't have a recession.
Therein lies the problem for investors, because it's one thing to say that the US economy has been doing better than, say, Europe or parts of Asia or Latin America. But on the other hand, it's not going to help you as an investor if that's already being well and truly priced into the market.