So a lot of people are saying supply chain or logistics without really explaining well. So I'll give it a try.
It is impossible to overstate how important supply lines are to fighting a war. Each branch of the military has a whole arm of their organization dedicated to getting supplies to where they are needed. In any given war this means setting up regular purchases of supplies, bases to aggregate those supplies, routes with bases for each leg of the journey of those supplies, and bases at the destination of those supplies. With dedicated protection for all those parts of the journey. Which still has to get from the in-theater supply hub to the front.
Ideally for a carrier group you would use massive supply ships in a daisy chain to maintain a continuous flow of supplies. The supply hub isnt supposed to be close enough to come under enemy fire, and helicopters are relatively short range and not suitable for this purpose.
So the problem is that iran has shown that with drones it can hit big slow ships in the gulf, and regionally can hit anywhere with balistic missiles and drones. So they damaged or destroyed most us regional bases, hitting the main supply hub.
What to do about that? Well they could set up another regional hub, but that would probably get hit too. They can use a base far enough away to not get hit, but that means relying on more big slow ships to maintain the steady flow, but they would need protection, except ts hard to say what protection can be given against suicide drones.
This is would be a huge headache or any career general with a lifetime of experience. What they have is a drunk tv personality who surrounds himself with sycophants, and who's taking orders from a geriatric child with dementia.
Add to this the longevity of the deployment. Most world militaries are very timid at exerting their big expensive assets at full strength unless its an actual war because that wears them out really fast. America is the only country that does this regularly. In other words, the deployment time for a carrier group is pretty well set in stone with some wiggle room. They know how long they can keep it up at full activity.
It's not even a matter of supplies, its a giant steel city floating on salt water firing jets into the sky shooting down potential threats when it cant evade them. This is a structure under stress that can't be fixed with a few nuts and bolts. There are parts that can only be overhauled at a port that have probably run long overdue.
The personnel problem is oddly the smallest. They could rotate people easily on the supply ships, if the whole shitshow werent run by such huge assholes.