Pretty much all of this is incorrect.They are obsolete because their big guns, characteristic of battleship, are terrible for shooting down planes and terrible for sinking submarines, and terrible for firing at agile destroyers/cruisers that can launch missiles that easily puncture holes in the armor of all battleships, sinking them before the battleships main guns can even get into firing range.
They are useless for modern day sea warfare unless you just want bunch of artillery on floating steel bunker for shore bombardment because that is what battleships are really, a floating bunker packed with heavy artillery.
First off, no missile afloat is going to penetrate an Iowa's armor.
Secondly...they aren't useless other than the big guns. They can serve as command ships. They can refuel their escorts and other ships.
They aren't designed to sink subs. Neither are carriers. ASW is mostly done by their escorts.
They can sit offshore and lob shells....and guess where roughly 80% of the high-value targets of any country that has a shoreline are? Yep, not far from shore.
BTW, the Iowas have missiles, too. Tomahawks and Harpoons. Would be more modern versions if they were in the fleet today, but in the 80's they carried the most missiles in the fleet. So that's not why they were decommissioned.
Further, they can shoot a lot farther than 20 miles or so. The tech was researched and ready for production in the 80's to let them shoot 50 miles or more. And research was being done to further that.
They are VERY effective at shore bombardment. Heavily armored, so they don't worry much about anti-ship missiles or artillery. In Vietnam, the VC were so frightened of New Jersey that they demanded she be removed from the theater before they'd agree to peace talks. THAT is effectiveness.
In the Gulf War, the Wisconsin visited Abu Dhabi. They were so impressed with her that they offered to pay for her operational costs if we'd base her there.
Plenty of use for a Battleship today. The crew requirements is what killed them, nothing more.
