Actually, the idea behind the firebombing was generated because the jet streams above Japan prevented the bombers from aiming their bombs anywhere close to the factories as the winds would cause the bombs to drift.
If the bombers went with jet streams, the apparent ground speed was too fast for the bombsights and they would overshoot their targets. When they were first trying to bomb the aircraft factories in Kawasaki and Yokohama, they would wind up dropping the bombs in Tokyo Bay, where the locals were joking that the US strategy was to starve the population by killing the fish.
Going against the jet streams put the planes too slow and vulnerable to AA fire.
The eventually came up with the idea of firebombing at night, where the B-29s could fly considerably lower than during daytime raids and avoid AA fire. They were flying at 5,000 to 9,000 ft, which was a difficult altitude for the Japanese AA. The Japanese night fighters were ineffective so they were able to remove their tail guns to allow the B-29s to carry more bombs.
Lead bombers would drop larger 100-lb napalm bombs to start fires for guidance and then the rest of the planes would drop their cluster bombs , which with 38 six-pound M-49 bomblets. The USAAF build replicas of Japanese homes at Dugway Proving Grounds in Utah to test the effectiveness of the bomblets.
Japanese homes were made of wood, crowded together and often stacked two or three deep from the roads, especially in the shitamachi, older sections of the cities. (I’ve posted a number of times about the experiences of my ex-wife’s parents, who were children living in different areas of Tokyo.)
It’s clear from the targets of the bombing campaign that they were not limiting themselves to housing around industrial, but rather were trying to burn Japan down to the ground.
The results speak for themselves. They were so effective, they were running out of targets by August, 1945.