Seattle, I don't know if we "need" more. But here are some thoughts.
Here's my perspective. Applying an analysis saying we have 10x more carriers than the next guy...why do we need more? Ignores several realities.
First, the current world order is unipolar with the United States as the sole superpower. Being the sole superpower is expensive, but it's an investment that saves lives. To have the power to call the shots and dictate the terms of battle, to have the flexibility and resources to decide when to and when not to fight saves lives. Let me put it this way...France, England, Russia, China...would LOVE to even consider whether 10 carrier strike groups was too expensive. We're fortunate that capitalism has provided us with a strong economy for our people to enjoy while also paying for the shield to protect their freedom.
Now, our position as the sole superpower is slipping. China and Russia are both engaging in a carrier building program. If China or Russia had just 5 carriers to control sea lanes and project power in their region, something completely possible, it would put our allies, our interest, and our people at much greater risk. With lives and national security at risk, this isn't just a matter of having a little more than the next guy - being a little better, it's about controlling the fight.
Second, threats we currently face today are asymmetric. The United States military, for reasons stated above, is not an asymmetric force. And while we have evolved our special forces capability to take on these threats...the power of carrier strike groups are a major force multiplier to our grunts. The ability to put a carrier off the shore of any country and provide immediate close air support, reconnaissance, search and rescue within 24 hours for our grunts on the ground is huge. You can't do that with Air Force assets. That requires foreign country clearance, treaties for bases, refueling, etc. The air support from Naval aviation saves lives. And we can do that because right now we have 10 carrier strike groups. Taking that down to like 8 severely reduces that capability. There are always carriers getting refitted/nuclear refueled (which takes several years), in workups to certify for deployment, or just getting back from deployment, etc. It would mean either carrier gaps or at sea deployments in excess of 9 months. Is the prospect of no immediate air support for special forces or troops in case of a major contingency digestible to the American people?
Third, cost of the craptastic F-35 aside, I think the evolution in UAV technology, weapon systems, and ship automation will eventually make the cost of buying and operating 10 or 12 carriers realistically about 80% of what it currently takes in real dollars. Now...to get there means we fix the f'd up procurement system. But that's not a technology or finance issue...that's a political issue.
