The B29 had a hellbunch of problems when first fielded in strength. The jet stream being a major problem. Its patently false though to claim that only two sorties had any im[act. You see, once Gen LeMay took command of the 20th USSAF and decided to strip the 29 of most of its guns and gunners and sent the things in at 10-12k at night using pathfinders to start small fires in the target cities the n hell started coming to Japan. This bombing brought heavy suffering to the Japanese and they lost severely needed industrial capacity and workers to man those factories. This low level night raid stuff coupled with the new indendiaries burned entire Japanese cities to the core. Nope, once LeMay made these adjustments the 29s started wrecking hell on mainland Japan. If the atomics had never come into the picture the 29s would have only increased in numbers and devastating impact.