Why did their roadmap lead there? Essentially, because it was against human nature. It turns out that "work for the good of all mankind" doesn't motivate as well as "work for the good of yourself and your family". They had to add "work for the good of all mankind, or be punished" in order for the system to work at all.
Now, the really interesting question: Will any system that has an agenda of economic equality end in the same place? Can any system have that as a goal, and produce a system of governance that isn't (approximately) equivalent to the USSR version? I suspect that the answer is no. If your humans have the same human nature as the humans of the USSR, then you wind up running into the same problems that the USSR ran into. If your system doesn't account for human short-sightedness, selfishness, greed, and laziness, it isn't going to work in the real world.