The youtuber, knowingbetter, pointed out that the reason aircraft carriers are seen as so vital in the pacific war is because the US lost most of its battleships at pearl harbor so had to default to carriers for major operations. It made me wonder how the war would have been prosecuted if the navy had its battleships.
Knowingbetter is a very entertaining YouTuber, but his historical analyses are a sometimes way off-base or overly simplistic. This is one of those cases.
Let's go to the section in question, from https://youtu.be/M4m_BwYeIRo?t=418
First off, his claim that "all of our battleships were either damaged or sunk."
This isn't even close to true. The six Standard-type battleships in the Atlantic Fleet (the USS Arkansas, USS New York, USS Texas, USS New Mexico, USS Mississippi, and USS Idaho) were obviously undamaged. The USS Colorado was in Washington undergoing an overhaul that was done by March 1942. And the brand-new fast battleships USS North Carolina and USS Washington on were on their shakedown cruises and ready for action.
As for the battlewagons at Pearl, the USS Pennsylvania was only lightly damaged and was soon ready to fight again. The USS Tennessee and the USS Maryland both returned to service just three months after the attack and the USS Nevada was repaired by late 1942.
New fast battleships also joined the fleet just months after the attack. The USS South Dakota was commissioned in March 1942 and ready for action by September. Her sisters, the USS Indiana, USS Massachusetts, and USS Alabama were ready around the same time.
The U.S. Navy had plenty of battleships available for action in the Pacific. However, there were other demands on the battleships. In November 1942, three battleships (Texas, New York, and Massachusetts) took part in the pre-invasion bombardment for Operation Torch. And, the surviving battleships were also too slow for some operations (more on this later).
His next claim is that "we were forced to use what we had left and we suddenly realized that these former novelty items were pretty dang useful."
"What we had left," included plenty of battleships. In fact, battlewagons saw plenty of fighting from 1942 onwards. The fast battleships (~28 knot top speed) of the South Dakota, North Carolina, and Iowa classes has been designed before the war to work alongside the carriers. That’s exactly what they did. They all served alongside the fast fleet carriers in as part of task groups during the war. Their extensive AA batteries defended the carrier from air attack and their main batteries deterred IJN surface attack.
The slower Standard-type battleships (21 knot top speed) were too slow to keep up with the carriers, so they spent most of the war doing shore bombardment during amphibious operations. The one notable exception happened during the 1944 Battle of Surigao Strait, when six of these old battleships (five of them resurrected Pearl Harbor survivors) sunk the battleship Yamashiro.
As for his characterization of carriers in 1941 as "novelty items" the U.S. Navy "suddenly realized were useful," this is just flat-out wrong. The U.S. Navy didn't suddenly discover that carriers were important just because the battleships were gone. By the mid- and late-1930s, carriers were already a major player in U.S. Navy fleet doctrine.
In fact, the U.S. Navy invested heavily in carriers well before December 1941. On July 19, 1940, nearly a year and a half before Pearl Harbor, the Two-Ocean Navy Act was enacted. It included provisions for seven battleships (two Iowa-class and five Montana-class) and five Alaska-class battlecruisers and eighteen new aircraft carriers, including ten new Essex-class fast fleet carriers. This was on top of three more Essex-class carriers that had already been programmed.
Carl Vinson, the chairman of the House Naval Affairs Committee, said at the time:
"The modern development of aircraft has demonstrated conclusively that the backbone of the Navy today is the aircraft carrier. The carrier, with destroyers, cruisers and submarines grouped around it is the spearhead of all modern naval task forces."
Fittingly enough, Vinson now has a carrier named after him, the USS Carl Vinson (CVN-70)
By December 7, 1941 the U.S. Navy already had the seven fleet carriers it had built in the 1930s, with eleven more carriers under construction. It wasn't as if Pearl Harbor and the ensuing campaigns of 1942 suddenly made the Navy go "hey, carriers are a really good idea, guys!"
So what was the U.S. Navy’s pre-war carrier and battleship doctrine? And how did this doctrine hold up in combat?
Continued…
While we are waiting for an answer to your specific question, you might enjoy this four part answer from /u/MerlinsBeard that describes how US naval plans adapted to the ships that were available.
I can't find the video you mention, but it seems like a self defeating argument to claim that battleships would have been more important than carriers if they hadn't been sunk by carriers.