https://en.wikipedia.org/wiki/Aleutian_Islands_Campaign"On 15 August 1943, an invasion force landed on Kiska in the wake of a sustained three-week barrage, only to discover that the Japanese had withdrawn from the island on July 29."
The month that this photo was taken, American forces discovered that the Japanese had already withdrawn from the Aleutians.
After the Battle of Midway, the sustained USN submarine offensive and island hopping strategy pulled the Japanese Navy closer to home.
The buildup that the Alaska RR and WP&Y were readying for was then no longer needed.
-Nick