The last time I checked there were very few airstrips in the middle of the ocean. Also when destroyers can fly then they can carry out alpha strikes for us. But you are right a land based airstrip is cheaper. he problem is the are a stationery target a CVN is always moving.
The moving part isn’t a big issue as anything that can sink a carrier can also find it and kill it. The issue is that such weapons cannot be launched within 100+ miles of a carrier and multiple weapon systems layered around the carrier can down those weapons. We spend more on carrier protection than we do on the carrier and its aircraft.
The one thing we cannot protect a carrier from is multiple ballistic missiles and the Soviets had created a warhead for their ICBMs that can find and kill a carrier. We created Aegis to counter it, but we also know they can overwhelm that system and get a warhead through.
So, to me, against a country a carrier is design to fight, it is an antique. Against ragheads and rusty AH-47s, it’s perfectly safe...until it gets too close to shore and a raghead State has a friendly relationship with a country like China. Of course, we will know it was Chinese and the Chinese don’t want a war yet.