In principle, this makes sense. But if you look at Japanese leadership at the time, even after two bombs were dropped, the military leadership still didn't wan

In principle, this makes sense. But if you look at Japanese leadership at the time, even after two bombs were dropped, the military leadership still didn't want to surrender. So a demonstration likely would not have achieved anything. Japanese leadership was zealous in the extreme, at a level that is difficult to understand from a modern perspective. The difference between Japan then and Japan now is an order of magnitude larger than the difference between America then and America now.