China is doing plenty about it by building out a navy that can counter the US, and to which every war game US themselves played they lost. They're also building alliances all across the Global South, and moving away from using the western financial system.

China is playing it smart here because they realize that time is on their side. The US is already stuck in two wars, and their resources aren't infinite. Meanwhile, US economic power continues to wane globally and its relevance along with it.