Why didn't America rebuild post-Soviet Russia much like we rebuilt Japan and Germany?

This was because the cold war started pretty much straight after Germany surrendered. Russia (USSR) became the new potential enemy to be feared and prepared against. (The US actually had a plan to nuke Moscow and Leningrad to avoid USSR becoming too strong during the end of 1940's but the plan was viewed as too risky and was dumped after The Soviets developed their own nuclear weapon in 1952.)

Because of the global rivalry starting straight away after II world war, The US would not help and The USSR wouldn't have accepted any help. USSR actually blocked Marshall-aid from countries that were it's allies or too close to it, to stop US influence from spreading. Such countries include for exsample Finland, that was neutral between the two superpowers and could not take in aid from The US for the fear of Soviet reaction.

/r/AskHistorians Thread