We have surplus carriers specifically to allow them to average a large percentage of their time at home unlike container ships who spend the vast majority of their time in service. Many systems that are both bespoke and complex means lots and lots of maintenance issues.
Sure the Navy can Airlift in parts etc, but that’s obviously very expensive and less obviously more dangerous.
We don't have a surplus of carriers. We have a shortage, at least relative to their current tasking. They're overstretched and behind on maintenance. This is unsustainable so the civilian leadership will have to either cut back on missions or build more.