Kamikazes were an indication on the Japanese side that they knew the war was lost and they were simply staving off defeat and making victory as expensive as possible. They had lost the initiative by then.
A winning army does not engage in Kamikaze, and Japan was no exception. It is only after most of their planes were shot down that they engaged in kamikaze, not before.
I believe the historic reason is that they had expended their trained aircrew, and that their fleet of carriers had been relocated to Davey Jones' anchorage. Japan's only aviation recourse was to try and overwhelm air defenses by mass and take one way trips. The Japs had plenty of aircraft, not enough guys for the skill positions to use those assets in a conventional way.
And? How long could they last? After Nagasaki they were still stalling in the face of naval bombardments and an 800 plane B-29 raid. The US would have been stupid to blockade and cease all attacks, the Japs need a convincing show of power. Fortunately they didn't know how many bombs we had, but there would have been three more by October. Had they not capitulated they would have got those as well.