Why alliance capacity is not the same as naval presence

Could NATO navies cooperate to protect shipping through the Strait of Hormuz?

They could cooperate, but only navies with ships actually present could respond promptly, which made persistent British and American deployments important.

Alliance capacity on paper differs from having ships nearby when a crisis begins. In this 2020 discussion, the Royal Navy and US Navy are identified as the Western allied navies maintaining a persistent regional presence rather than relying only on visits. That presence reflects responsibility for protecting merchant vessels under their own flags and those of states they support. NATO members cannot escort or protect shipping through the Strait of Hormuz with forces that are not already deployed or close enough to respond.