I see what you mean.
I guess we'll never know. Because there was a remaking of Japanese society after the war in a democratic image. That just doesn't even appear as though it was attempted in post Soviet Russia.
I don't kmow the origins of why America departed from its usual course of propping up the traditional land owning and wealthy bourgeoisie classes in it'
s occupation of Japan. I know FDR personally held very pro democracy and anti colonialist views. He had ambitions to remake America's relations with the developing world after the war though how far he would've progressed on that front is unknown. And of course he was dead by the end of the war and Japan was in the more conservative hands of Truman.
Perhaps the Japanese people ran with this program because of their cultural tenacity. Or perhaps because their defeat had been so total that they truly considered themselves defeated and simply wished to move on whatever with whatever power structure was presented.
Ultimately though, America began a campaign to turn the "subjects" of the Japanese Empire into "citizens" of a Japanese constitutional state. They did not undertake a similar project to turn "comrades" of the Soviet Union into "citizens" of a Russian Republic.