The decline of the "big gun" was more messy history. There were only three major post WWI navies: RN, USN and IJN. Each were really fascinated by the aircraft carrier. (Loonies like Billy Mitchell did their best to obscure the obvious here.) The big question mark was aircraft capability which was increasing at a break neck rate, while the developments in naval architecture were slowing down. (This does not count communications, radar and sonar.) Ships and planes went through remarkable development curves. In 1870 a "state of the art" warship was HMS Warrior. Fifty years later you had things like Texas or Bayern. Ships were obsolete the moment they were launched for a generation. Then you got what seems to be an inevitable phase reflecting the law of "diminishing returns." WWI dreadnaughts were not only good, they were good enough for WWII. As Churchill put it, WWII was fought with the ships of WWI. When you count beans, the number of modern "fast battleships" in all the world's navies was very small by 1944, especially if compared with the pre-WWI naval race.
Aircraft were taking off just as ships were slowing down. A young aviator could have received his wings flying a Pea Shooter and retired looking at a new F-16. So postwar admirals all knew airplanes were sweet, they just didn't know how sweet. And they didn't know because it was not possible to see what an airplane would look like five years down the road. Carriers were recognized almost from the start as "big ticket" items that were meant to last for a generation just at at time when aviation was moving from a Spad to a ME-262 in 25 years. So when war clouds started gathering, admirals started arguing about priorities. That the CV was going to be king was obvious. The question was when the coronation would take place. The other question was how would they actually be used. None of this was clear. So when governments started to write big checks, the reflex was to build BBs along with more CVs. The 1940-41 Navy bills passed by Congress called for the construction of, I think, a dozen new BBs. They ended up with the four Iowas. The other four fast BBs had been authorized along with the Yorktown, Enterprise, Hornet and Wasp. In the long run the USN couldn't build the number of carriers approved on paper after Pearl Harbor either. (In fairness to Congress, many were thinking of "fortress America" and were not contemplating a massive army and air force competing for resources. People laughed when FDR called for 50,000 airplanes in 1940: we built 400,000.) Anyway, by December 1941 the carrier had already shown itself as the heart of the fleet - Pearl Harbor only drove home the point. So, aside from the four Iowas already begun, BBs were canceled by the USN. Japan and the UK had already made that decision.
But what about the ships already there? Nobody was thinking of sinking Texas, much less Washington. The Brits were building DDs by the billion but weren't about to scuttle KGV. A lot of Japanese admirals had already seen that the Yamato gamble had been a mistake, but you weren't going to plant flowers on the deck and make it a theme park. The major role adopted initially by the BB was the protection of troop movements. (Every naval battle in the Pacific war was triggered by the movement of troops.) Shore bombardment was, surprisingly, controversial because it endangered the battleships. One reason the IJN didn't annihilate Henderson was that their BBs didn't have sufficient supplies of the new dedicated HE shells - it was simply assumed that a BB would fire armor piercing rounds. That sure changed. And along with it became obvious that you could put a lot of flak on a BB so in the USN, fast BBs became the centers of the carrier task forces. It wasn't a cost efficient way to do things, but it was a way to do things. And in everyone's mind was the possibility of a carrier stumbling into the range of a BB. Brits lost Glorious. The Med was never considered good "carrier country." Hornet was sunk by Japanese destroyers. (Ours couldn't do the job thanks to their miserable torpedoes.) It was because of this role that BBs intervened in the incredible shoot-out of November 15 on Guadalcanal. South Dakota and Washington were deployed when Halsey decided to temporarily land base the Enterprise air groups on Guadalcanal and get the carrier itself out of Dodge City. Good move. Enterprise aircraft helped demolish Japanese shipping, including BB Hiei: Washington demolished Kirishima the next night.
So even though it was cheaper to build ten Fletchers than one Iowa (about the same number of crewmen) and the DDs could carry over twice the number of 5'38s (and fight subs too), they couldn't be asked to stare down a chance encounter with an enemy BB - or so people assumed until Leyte. And DDs sunk. BBs didn't. It was beastly hard to sink a BB. A Kamikaze pilot who hit a BB really did waste his life. So BBs played a surprisingly important role in WWII because of capabilities in hand and as an answer to potential dangers. It's no surprise that the world said good bye to BBs in 1945. It's also no great surprise that the USN put Iowas back into the water periodically for the next fifty years. They could chuck a shell the size of a Volkswagen nearly 20 miles, and something like an Exocet would barely scratch the paint. History is messy.
Over and out on this thread. Think I'm going to build a biplane.
Eric