The U.S. Navy is not a very flexible force.
Out of 275 ships on the Navy’s “Battle Forces” list, fully 23% of the Navy’s ships are Arleigh Burke-class “destroyers,” and 25% are nuclear submarines. Throw in a few Ticonderoga-class cruisers (8% of the fleet) and 10 operational aircraft carriers (4%), and well over half the fleet is made up of just four types of warship.