“Replace.” They couldn’t replace planes. Or ships. And they never would be able to do so.
Imperial Japan had run out of gas. Literally. They hadn’t the fuel to continue the war, they hadn’t the pilots, and they weren’t going to be getting off the ground, which even kamikaze pilots require.
Are you trying to say the use of nukes was unjustified?
Sure Japan in the end had severe fuel shortages, but Kamikaze pilots require very little fuel. Regards
Admiral Matome Ugaki was recalled to Japan in February 1945 and given command of the Fifth Air Fleet on Kyūshū. The Fifth Air Fleet was assigned the task of kamikaze attacks against ships involved in the invasion of Okinawa, Operation Ten-Go, and began training pilots and assembling aircraft for the defense of Kyūshū, the first invasion target.
The Japanese defense relied heavily on kamikaze planes. In addition to fighters and bombers, they reassigned almost all of their trainers for the mission. More than 10,000 aircraft were ready for use in July (with more by October), as well as hundreds of newly built small suicide boats to attack Allied ships offshore.
https://en.wikipedia.org/wiki/Operation_Downfall#Kamikaze