One of the few things Admiral Zumwalt got right was the concept of the high-low mix. In fact he didn't invent it; as Friedman (and others ) have pointed out, he was merely pointing out the state of affairs then existing in the USN surface force. From the 1920s until the 1990s, the USN sustained its overall numbers on the back of construction from the previous war. One of the problems facing the USN today is that it has very nearly finished burning through those ships and has not come up with a satisfactory replacement.
The problem is that the US has never been very good at building second-rate warships. This has its roots in several places. I think one of them is the lack of a serious imperial experience; the 19th century Royal Navy was forced to develop a high-low mix in order to maintain its Empire - sailing battleships to keep the peace in Europe, small men-o'-war to police the Empire. Another place is Mahan; he divided navies into those that controlled the sea and those that denied the sea, and the general interpretation of his theory was that sea control required a fleet of battleships. The USN, without the Imperial responsibilities of the Royal Navy, never quite got the idea that sea control requires both a fleet of battleships (aircraft carriers) that can defeat a rival fleet (or deter it from fighting or even being built) and a fleet of smaller ships to conduct the day-to-day business of sea control - fighting pirates, knocking the odd local chief on his head, etc. The closest we got to acceptance of a high-low mix was building ships intended to defeat sea-denial navies (ie, anti-submarine vessels.) Another is the American cultural tendency to go with the biggest, best (and most expensive) thing out there.
So - a country culturally disinclined to build cheap ships, which early in its history did not need to build cheap ships and developed a naval theory that called for expensive ships, has a navy which tends not to build cheap ships. This should come as no great surprise.
The problem is that we now have a very different naval problem than ever before.
During the 20th century the US filled the "low" end of the high-low mix with leftovers from the last war. During WWII, the low end was made up of destroyers left over from WWI (augmented by new ships that were mostly too late to be much help.) During the Cold War, the low end was made up of destroyers left over from WWII, augmented by new ships that were intended as their replacements, but were never built in sufficient numbers to fully replace them. Since the end of the Cold War, the low end has been made up of ships left over from the Cold War, which have been augmented by...nothing. These Cold War leftovers have mostly been used up by now, and there is still nothing to replace them - at a time when the US has, perhaps for the first time in its history, a need for cheap ships not necessarily intended to counter sea-denial fleets (ie, we need the low end to do something other than ASW.)
We are not good at building these.
We need to get good at it.
The current Naval culture does not fit the current Naval mission. We have a Naval culture that thinks in terms of building the latest and greatest without reference to whether the latest and greatest is actually very useful. Sometimes it is. Our aircraft carriers are the latest and greatest - and they should remain so. The USN has had no peer competitor since 1945, and the power of our carrier force is part of the reason why. Its very existence guarantees our freedom of the seas. The USN has also gotten very good - thanks in part to the inherent advantages of air power - at using its carrier force for the day-to-day work of sea control. But aircraft carriers and their escorts cannot be bought in the numbers necessary to do everything, which is why we need a low end.
However, the modern USN has proven unable to build a proper low-end ship. LCS should have been that ship, but it isn't. It is too weak to be a high-end ship and too expensive to be a low-end ship. It is a dead end.
The USN needs to rein in its tendency to gold-plate everything. It cannot fulfill its mission if it does not. This process will be difficult. The military-industrial complex has evolved a major political component that adds major complications to any effort to build a cheap ship. But all the players are facing hard choices. The Navy should decide whether culture is more important than mission. Industry should decide whether it can make more money selling a few expensive ships or many cheap ships. Politics should decide the Navy's mission - whether it is a battlefleet, a sea control fleet, or a jobs program.
I say "should decide" rather than "must decide" because nothing I have seen gives me any indication that any of these actors "must decide" anything, or at least believe that they must. They seem content to muddle on, fiddling while the Navy burns. But indecision is a choice, too, and like any choice, it has consequences. At least choosing a course of action would convey some choice of consequences. Instead the Navy sails on, rudderless, into an uncertain future.