The Japanese were prepared to fight to the last man, woman, or child to defend the home islands. They were geared for war in a way that is hard to understand from a modern perspective. They were propagandized heavily.
The other thing to recognize was that the USSR had declared war on Japan the day before Fat Man was dropped on Nagasaki. This violated the Soviet-Japanese non-aggression pact. Before this there was hope that the Soviets could advocate for better terms for Japanese surrender. The Japanese Supreme Council was firmly opposed to ending the war. After Nagasaki, Hirohito intervened in the council and ended the war.
The conventional ordinance dropped on Tokyo killed many more people than Little Boy killed in Hiroshima. The Japanese barely surrendered after the nuclear attacks. I would suggest listening to Dan Carlin’s Hardcore History miniseries Countdown to Armageddon if you want to know more.
Also, RadioShack in spirit - it’s called The Source now and it’s on the death knell, but they’re still around.