Midway is part of the answer, but again only part. It was the 12 months following Midway, and specifically the last 6 months of 1942 that firmly gave the Allies operational freedom and momentum that they retained for the rest of the war in the PTO.

Midway was crucial for the most part because it bought the US temporary operational breathing room. Until a new Kido Butai could be organized around the former CarDiv5(Shokaku and Zuikaku), Nimitz had the only operational carrier force and King in DC wanted to use that. The loss of 4 fleet carriers left the IJN with just the 2 true fleet carriers still recovering from Coral Sea, while Nimitz retained 3 with a 4th on the way, the best odds they had had all war. In particular he wanted to secure the sea lanes to Australia he had been so concerned about for the first 8 months of war. Reports of the development of a new Japanese airbase in the Southern Solomons to add to their seaplane base at Tulagi only added extra force to getting an offensive off. By striking arguably before the US was ready too in early August at Guadalcanal, King achieved this if by a narrow margin. He had broken the IJN's decision making cycle and for the first time on a strategic scale made them react to him.

And react they did, in 2 mostly indecisive carrier battles that saw the US retain control of Guadalcanal, numerous surface actions, and routine and bitter bombing raids. The fighting in these months was not easy on the USN, a score of small ships sunk and more damaged, 2 carriers(Hornet and Wasp) lost, another (Saratoga) forced back to the US for repairs along with 2 battleships. But in return several key fleet units of the IJN including 2 battleships, a light carrier, and numerous precious transports were sunk. And most importantly the elite of the IJN air crews were butchered. The pilots of 3 of the carriers came through Midway pretty well, and were fed into the rebuilt Japanese carrier force, or to shore based units, and in early 1943 many more were fed into Rabaul or units in the Gilberts and Marshalls. It was the killing off of these crews, while the USN crews that had fought up to Midway were mostly sent back to training assignments, promoted to command, or used as cadres for new raw units further served to hamper IJN aviation quality. All this along with some of the most violent, terrible ground combat of the war between the Marines and Army on CACTUS and the IJA and SNLF.

By the end of 1942 the IJN had accepted Guadalcanal could not be held,a nd actually helped execute a daring and largely successful evacuation fo the remaining troops from that hellish island. And from there for several months the war took on a new quality. The IJN was no longer willing to risk its remaining battered carriers, basing more aircraft out of Rabaul and other islands. While USN was down to just 2 decks, and for a while 1 with the Saratoga alone in SOPAC and partnered with the loaned out HMS Victorious.

But as Spring tuned to Summer the US and Allies began to change things. The targeted killing of Yamamoto was pulled off, new long range aircraft and better models like the Hellcat and Corsair arrived in numbers. And as summer moved on the offensive up the Solomons and New Guinea resumed. And the fall of 1943 saw the US kicking down the door on the Japanese island defenses in the central Pacific with the Gilbert and Marshalls operations. Underwritten by a new carrier force including the first 5 of the new Essex class carriers. Paced with the US also executing major airstrikes against Rabaul in late 1943, including by carrier, to neuter what sea and air power remained at the base.

As argued by Shattered Sword and Islands of Destiny Midway bought the US room. But it was the Solomons that drained the remaining strength of the IJN and IJA to fight the war on anything like equal terms. Though this would only become crystal clear in the second half of 1943 after both sides spent the first half of that year preparing for the next phase of the war.