Chinese luxury spending has stalled, prompting brands like Louis Vuitton to increasingly rely on the US market. America's "wealth effect" from stock gains, notably in AI, currently fuels top-end purchases. However, the author warns of significant vulnerability should the US stock market decline or an AI bubble burst, reversing this dynamic. Chinese government measures targeting the wealthy and broader economic malaise further dampen luxury prospects there. Brands fear a repeat of previous simultaneous market weakness in both major regions, highlighting the precariousness of their current growth strategy.