I was always worried we weren’t building up the support for the big ships and combat. Do we have the cargo ship tonnage needed to move massive amounts of equipment and supplies if a war broke out?
No.
Worse, we don’t ven have the industrial ability to build the industrial capacity to BEGIN building the shipyards and armories and factories to BUILD that military.
In WWII, it took a buildup starting (slowly!) in 1938-39-40-41 to BEGIN the growth using Depression-era empty factories, steel mills, and mines and foundries! - to have airplanes and rifles and cannons and ships delivered in 1943 and 1944 and 1945.
I recall during POTUS #40 RWR's watch that he was trying to get us to a 600 ship Navy. Today we are < 300. Even if we had a merchant marine force to transport men/supplies, it would have to be defended - just think of the U-boat slaughter of the convoys in the North Atlantic during 1940-1943.
I was just thinking of our Army airborne divisions. With the world being flooded with MANPADS today, It seems almost suicidal to do a combat drop. I think the last 1 was in Aghanistan, not long after 9/11, an airfield assault somewhere between 2001-02.
As far as replacing carriers goes, the problem is sustained response. Yes, we can launch missile strikes from surface combatants, submarines and long range bombers, but those missiles are very expensive for the amount of explosive you are delivering. The result is that a large missile strike at the beginning of a conflict severely depletes our stores. Tough solution.
Take a look:
US Military Sea Lift Command Vessels
These are not officially a part of the US Navy anymore. They are not "USS" vessels, instead, they are "USNS" vessels. Usuallu crewed mostly by Merchant Marines with small US NAvy detachments for communications and operations.
We have a lot of really big ships to move mountains of supplies and have in fact pre-positioned loats of it at places like Diego Garcia, Guam, Saipan, etc.
I know, we'll rent them from China!
Oh, wait... :)