Earlier quoted context omitted.
Do you think a continuation of the firebombing campaign and an invasion of the Japanese home islands would have resulted in fewer deaths of civilians (particularly of the 'volunteer fighting corps')? That's to say nothing of the deaths in a potential US/USSR conflict that goes hot without the Damocles Sword of MAD...
This is a false dichotomy. In the words of the post-war US strategic bombing survey: "Based on a detailed investigation of all the facts, and supported by the testimony of the surviving Japanese leaders involved, it is the Survey's opinion that certainly prior to 31 December 1945, and in all probability prior to 1 November 1945, Japan would have surrendered even if the atomic bombs had not been dropped, even if Russi…
Because the Japanese were still fighting, the wartime economy was still trying to produce what it could, and the Japanese government was arming and instructing its civilians for fighting.
Post-surrender, it’s easy to say “we were planning to surrender”, especially to save face and pass the buck to the Americans for what the Japanese government brought on their people by continuing to prosecute the war effort.