The U.S. Navy is reconsidering its plans for expanding the fleet from its current 294 warships to 375. The navy has noted that ships, especially expensive new designs in the works, are more capable than existing ones. This means fewer ships are needed to get the job done. Part of the job is keeping ships cruising off distant shores. But the success of the new Sea Swap program (which rotates the crews every six months by flying the sailors to where the ship is, rather than the ship steaming all the way back to the United States) allows the navy to maintain the same number of ships in distant locations with a smaller fleet. It can take several weeks for a ship to get to and from a distant assignment back to North America, so now ships spend more time out there, and less time just traveling back and forth. This particular idea has been rattling around the navy for decades, but until recently never had enough admirals at the top willing to try it. The idea is an old one. The SSBNs (nuclear subs carrying ICBMs) have been using two crews since the 1960s. This was so the SSBNs could stay at sea longer, without turning off the crews (who are difficult to recruit and expensive to train) with excessive time at sea.
The new classes of surface ships (the DDX and LCS) will also have much smaller crews, and better crew living conditions. This will mean a smaller, in terms of personnel, navy as well. But each sailor will be more highly trained and more difficult to find and recruit. Thus keeping these folks happy will be a higher priority.
The navy is also reconsidering the size of its SSN (nuclear attack submarine) fleet. Currently there are 55 of them. There used to be nearly a hundred, at the end of the Cold War. But there is no more Soviet Navy, whose huge SSN fleet was the reason the United States had so many of these expensive (currently, two billion dollars each) boats. While there is no longer much of a threat for the American SSNs to deal with, the submariners have been trying to hide that fact by taking up new tasks (carrying and firing cruise missiles, doing recon and other intelligence work.) But the navy finally realized that there are cheaper ways to do those jobs. So one or two dozen SSNs may be retired, and not replaced.
As a result of all this, the future navy might be the same size it is now, about 300 warships. Or perhaps even fewer, as more robotic ships, subs and aircraft enter service. The robotic ships and subs are quite small, but they greatly expand the capabilities of existing, and future, warships. The navy has realized that technology is changing the concept of what a warship is, and that the ship count does not mean as much as it used to.