As I recall, when Curtis LeMay’s B-29 Superfortresses switched from high-level daylight “precision” bombing (which wasn’t as precise as they’d hoped) with conventional explosives to low-level nighttime area bombing with incendiaries, the effect on Tokyo and other large cities was to kill more people and destroy more property (much of Tokyo was built of wooden structures) than would ultimately be lost at Hiroshima and Nagasaki. It was a more labour-intensive and time-consuming process than the two atomic bombings, but its effect was still devastating.
One of the reasons Hiroshima and Nagasaki pushed Japan into surrendering is that those two blows came at the end of two processes which had already ruined the country. The first was the US submarine blockade of Japan, which over the course of several years starved Japan of vital imported resources. The second was the US strategic bombing campaign, which over the course of several months leveled many of Japan’s great cities. The A-bomb attacks, which flattened and incinerated two cities in just a few moments, were a quantum leap upward from conventional bombing, and they provided the final shock that persuaded the Emperor to agree to the terms of the Postdam Declaration.
Regarding Mallery’s observation that “isn’t it funny people talk about Hiroshima/Nagasaki, yet completely leave out or don’t know about the March Air raids that killed about 100K itself and leveled a good portion of the city with napalm and other substances?”, I suppose one possible answer is the one given by the fictitious Professor Groeteschele in the movie Fail-Safe when he talks about the devastating bombings of Hamburg and Dresden and Tokyo, then says that he’s omitting Hiroshima and Nagasaki from the list because those actions “belong more properly to WWIII than to WWII.”