The naval cost of policing global sea lanes

In this interpretation, global maritime policing is a burden that major powers often inherit reluctantly because secure trade benefits everyone while the provider pays much of the bill. A navy performing that role must disperse ships in peacetime instead of keeping its whole force concentrated for one regional war. The United States has spent heavily to combine worldwide presence with enough concentrated combat power, while allied carriers help share that load. China benefits from open sea lanes and may eventually face the same choice between relying on another navy's security work and committing more of its own force abroad.