The United States Navy is shrinking and our missions aren't.
So we have to do something. This article lays out the somethings options.
I have another idea. Set a number of platforms that we need to perform the missions we need to protect ourselves. Then build ships to reach that number.
Oh, they don't all have to be Ford super carriers or high end Aegis cruisers/destroyers. We really can build some less capable and cheaper ships for many missions. Remember, our fleet is composed primarily of high end ships, unlike the past when we had a core of capable ships and then cheaper, less capable, and more numerous escorts. In a version of grade inflation, our destroyers are no longer the cheap tin cans of World War II but high end ships that are amongst our most capable.
Further, a lot of missions in more sensitive areas (that is, sensitive to US military presence) but low threat levels, or humanitarian missions, can be carried out by modularized auxiliary cruisers.
If numbers really are important--and I think they are--we can get the numbers. Yes, because of geography we have to build larger ships capable of sailing long distances, so we can't just build small corvettes the way many nations do, who just need to sail out of their port to reach their patrol area. But we could have a real high-low mix with a low end based on basic ships with decent weapons systems that could be augmented with mission packages, which we are building for our littoral combat ships (LCS) class, if the balloon goes up for a bigger war against a more capable foe. We already use neutered Perry frigates that no longer have their missile launchers. Why not build new, cheap, frigates designed to accomodate mission packages that turn them into potent warships in war time?
We can't go on the way we are with shipbuilding. There won't be more money for the high-end ships we build (and no, the LCS are no longer low-cost ships). And we shouldn't reduce our deployments and missions to match reduced numbers that will result from our shipbuilding plans.
We really do need numbers. And we can get them. We shall see if the Navy really thinks numbers are important.