The United States is a great example of a progressive idea that succeeded. Like all such ideas, it moved from being a progressive idea into an establishment to be conserved. Despite the lack of recognition of its historical roots by the group that yells the loudest about saving it.That's a myth, because no Western European countries are socialist. They are all Capitalist. And they don't have a higher standard of living. I lived in Germany for 5 years. Most homes (lower and middle class) don't have A.C., dryers, kitchen appliances (dishwashers, stoves, refrigerators). Taxes are insanely high, you can forget about freedom of speech, heck you can get arrested for telling a joke.....
No thanks I'll stick with the good old U.S.
What I question is if socialism is so great how come the people that want it, just move to a socialist country? Go learn the language, move there, and take advantage of, then be apart of the socialism you so much love. Surely they would accept you with open arms.
Of course, the success of one new idea does not mean that all new ideas are going to be equally successful. Historically, major efforts to establish socialism have been susceptible to easy and often quick replacement by authoritarian rule. While this can happen to other forms of government including democracies and republics, it seems to be a major flaw for those that centralize authority in a large, controlling regime.
If social engineers can figure out how to get around that major obstacle, while maintaining individual rights and incentives, they may be able to move it successfully, but I cannot think of how that is possible.