Defense spending in the Western world is under tremendous pressure. We aren't going to have more money while we face the massive deficit and debt problems that have accumulated in the West over the last couple generations. For the United States Navy (and other navies), which counts its assets in smaller numbers than the other services, fewer hulls will be laid down or kept in service, which will affect the size of the fleet decades down the line.
So we will produce fewer ships. And because we produce fewer ships, unit costs will increase per ship. Which will result in fewer ships. Which increases the unit cost. How's that for a death spiral?
As I argued many times on this blog, numbers matter for the Navy. We speak of the tyranny of distance that constrains our ship design because we have to travel long distances to fight (and mind you, I'm not saying I'd rather have the strategic situation where we could build small, heavily armed ships with low endurance that only have to leave port to engage the enemy), but there is a tyranny of numbers, too. One high quality ship that can beat any conceivable foe simply can't be in two places at once.
And with numbers of hulls dropping, we will face more and more situations where we need more hulls than we have. The world isn't shrinking and the problems sure aren't shrinking. While it is nice that we try to make more of our existing hulls by using multiple crews or forward basing some ships to avoid the time it takes to transit from home port to deployment station, those measures are only useful for peacetime and don't address the problem of having too few hulls to endure many losses in war and still carry out our missions. If a ship is damaged or sunk, it just doesn't matter if the hulk is forward deployed or if there is a fresh crew ready to fly out to man the non-existent ship.
My notion is to bulk up with Modularized Auxiliary Cruisers.
This post at Think Defence expands on the idea to include not just long-endurance container ship-based auxiliary cruisers but also faster but lower endurance catamarans and movable but robust barges (with this as an example) for point defense. I'm basically a land power guy whose interest in naval affairs stems from the need for naval power to get our land power anywhere we might need it. So I'm glad that this idea is being pursued by others with more knowledge and interest than I have on the idea.
The Think Defence post notes this DARPA interest. I guess I'll always wonder if my post had any influence on that idea. Even before that post, I did notice hits from some interesting sources on my source posts that led to the more in-depth article/post. Although I will say that another idea I broached in an article some years ago (as part of another subject) was already in motion and I simply didn't realize it. Great minds (or just adequate, in my case) think alike sometimes and come to the same conclusions given the same problem and similar data. There are other links of interest, too.
I'd rather have purpose-built warships. But until we can afford them, we need to muddle through with 70 percent solutions (or even 40%, I'll admit) to maintain the numbers we need. Auxiliary cruisers, auxiliary corvettes, and auxiliary anchored bases are one way to get the numbers.
Sometimes muddling through is all you can do.