Because we can.
That’s why we built the Alaskas. Other nations scraped together resources to build what they desperately needed. We built stuff just because we could. Like B-29s that carried atomic weapons.
But that was when we had industry...
That is probably next to impossible now. No steel mill in the United States can manufacture 18 inch thick Krupp process armor steel needed for the turrets, barbettes, armor deck and armor belt. You may be able to cannibalize two Iowa class BBs for their barbettes, turrets and mark 7 guns. but why, without missiles, the enemy is safe if they stay 25 miles away from one.
I would think a guided missile heavy cruiser with some 8-10 inch guns would fit the bill nicely.
We need a new class of warship—small battleships armed with rail guns. With rockets and Anti-sub gear! A heavy cruiser for the 21st Century. Name em after Native American Tribes like Monitors in the Civil War.