I think you misunderstand. I meant to reintroduce battleships, i.e. redesign and build new ones. The last battleship design(Iowa-class) introduced was in the 1940s. Methinks something better and more effective/capable could be thought up with the wonders of modern engineering. And you can always make new parts.
Do you realize how much a battleship would cost nowadays?! And what type of weapons would you put on a modern battleship? The really big guns of old? Battleship guns have not been made for over 60 years, is it really worth the investment in research and development needed to make new battleship guns? That would be needed because I am fairly sure the largest naval guns made in the last 50 years have been 6 inch ones. A gun turret on the Iowa class needed a lot of manpower, requiring a gun crew of 50-60 sailors.
That is just the gun piece of the equation, what about the entire research and development cost for a new class of capital ships? The Navy has to constantly defend its massive investment in carriers, a battleship just does not bring enough to the fight for the investment required.
Only one country has made an attempt since the end of WWII to make a battlecruiser/battleship equivalent, the USSR with the Kirov class 'cruisers'. Arguably they were modern versions of battlecruisers, and what did they bring to the fight that an Aegis cruiser or destroyer doesn't? About 30 more missiles? That's it for that much investment?
I am about as much as a fan of battleships as anyone, one of only two reasons that I would have volunteered to be a SWO, but they are just not practical in today's Navy and the wars we now fight.