In one of the battleship groups that I am a member of on social media, the subject of the “end of the battleship era” came about with the suggestion that, after the Battle of the North Cape in December of 1943, the importance of post-Washington Treaty battleships had diminished so significantly that any WWI vintage battleship would have sufficed for the remainder of the war as battleships became shore bombardment (which the Iowas were still around for as late as Desert Storm) and anti-aircraft platforms rather than meant to kill other battleships in surface warfare.
Of course, this neglected the glaring fact that the October 1944 Battle of Surigao Straits existed.
As far as my take, I’d argue that the end of the “battleship v. battleship era,” in which opposing vessels of the type could have possibly met in combat, was the mid-to-late 1950s.
Between the three Sovetsky Soyuz-class (Project 23) battleships still somewhat under construction until the late 1940s (canceled 47-49), as well as the elderly Great War-era Gangut-class dreadnoughts (Petropavlovsk/Volkov, stricken 1953; Gangut/Oktyabrskaya Revolutsiya, stricken 1956; and Sevastopol stricken 1957), and the old Italian Cavour-class battleship Giulio Cesare which was taken over after WWII as Novorossiysk until she blew up in 1955, the Soviets had several kinda operational battlewagons as well as some intermittently on the drawing board.
Meanwhile, arrayed against the Red Banner Fleet were a number of active NATO-controlled battleships including the Turkish battlecruiser Yavuz (old SMS Goeben, retired 1950, scrapped 1973), two French Richelieu-class battleships (Richelieu and Jean Bart moved to reserve in 1957), the Royal Navy’s HMS Vanguard (retired in 1960), USS Mississippi (still in commission as a test ship until 1956 and retaining her No. 4 turret with working 14-inch guns as late as 1952), and the four Iowas (mothballed between 1955 and 1958, although they would make a rapid comeback). Plus, the reformed Italian Marina Militare (which was a NATO fleet from the organization’s first days) still had the ancient Andrea Doria and Caio Dulio on the rolls as late as 1956. Going even further, the U.S. Navy had 11 very recently modernized dreadnoughts (nine with 16-inch guns) of the Tennessee, Colorado, SoDak, and North Carolina classes in mothballs but still on the Naval List as mobilization assets until 1959.
In short, had there been some sort of East vs. West dustup in the early days of the Cold War, especially in the Black Sea/Eastern Med, it could have resulted in a scenario where battleship-on-battleship violence could have occurred as late as 1956 or so.
Or at least that is my take on the debate, anyway.