The end of WW2 saw the end of the battleship as a necessary weapon of war by the major industrialized countries. Actually, they discovered this fact just after Pearl Harbor when a few Japanese aircraft took essentially the whole battleship portion of the US Pacific Fleet out. Those same aircraft finished off all of Britain's big ship assets shortly thereafter as well.
When trying to find where the old British battleships went, the hunt went cold at the scrapyards. They've all been scrapped, the last one (HMS Vanguard) in 1960. The Brits obviously don't think they will ever need them again, and they probably won't. The US's ships have fared much better. Of the last 2 in US active service, the USS Wisconsin has been decommissioned (again) and resides in the National Maritime Center-Nauticus in Norfolk, Virginia, and the USS Iowa was decommissioned in 1990 and resides in a mothball fleet in Suisun Bay, California.
So, not only does the US still have those 2 ships, they still have lots of them that survived WW2 around somewhere. Ships that have been fixed up and used as floating memorials include the North Carolina, Alabama, Massachusetts, Missouri, and the New Jersey. The USS Texas, the only one to survive WW1 and WW2 is being restored in LaPorte, Texas. So it seems that if we need them again or not, it's kind of comforting to know that all those big guns are still around.