Aircraft carriers are very expensive to run, about the same as a battleship actually. And the Iowas did have a modernization done that added:
- 32 × BGM-109 Tomahawk launchers (8 Launchers x4)
- 16 × RGM-84 Harpoon launchers (4 Mounts x4)
- 4 × 20 mm Phalanx CIWS
And even then, they where still seen as a colossal waste of money, even vs an aircraft carrier (that can do more and is real "force projection") that was seen as more vulnerable then an aircraft carrier. That was in the 1991 and now? 34 years later? They would be the biggest waste of soon to be sunk money in modern warfare.