I don't think it's that simple. Unlike post war Germany, the Russia that emerged from the cold war wasn't a functioning democracy but more of a kleptocracy. Yeltsin got put in power by a military that saw him as a convenient stooge.
And with Yeltsin, corruption and nepotism flared up almost immediately. So any kind of Marshall plan would have deteriorated into providing billions to oligarchs. Which is of course what happened in any case. And of course eventually the KGB and Putin took over with all their institutional paranoia regarding the west. Allegedly, Putin might actually be the richest person on this planet at this point. It's hard to estimate his exact wealth but he's not a poor man, to say the least.
You are also forgetting, that Russia was still a powerful nuclear capable force after the wall came down. There was no military defeat. And there were plenty of olive branches in terms of investments and collaboration. But, the Russians weren't exactly open to the US dictating them how to run their country. Germany had no choice in the matter. It was occupied by the allied forces and ruined by WW II.