Maybe, but they've also been well assisted by those countries which are shining examples of SC&L but have failed to get their messages across the world. Perhaps replies to this comment could indicate which countries those are, for some independent research.
This propaganda is coming from the most prosperous, overachieving nation in the history of mankind, so it seems like there might be something to it. Now the propaganda coming from impoverished, third world countries saying how all their problems can be solved through communism, just doesn't have the same luster for some reason.
Now if you can point me to an example of a utopic nation where everything is wonderful and workers run the show, I'm all ears.