I wonder... after all communism/socialism has been around as a force since, oh, the mid 1860's to the present; it has been proved a bloody failure (literally) again and again in any way, shape, or form no matter where its been tried, and yet there are no lack of believers, or politicos, eager to try it.
True, but there is a distinct difference between political philosophy and scientific theory. There was a time when "the church" and scholars of the day alleged that those who claimed that the earth revolved around the sun were heretics and some were executed for their beliefs. The science eventually exonerated the "heretics".
At the time that Columbus sailed the ocean blue, people believed that the earth was flat and most believed that Columbus would sail off the end of the earth. Again, science (and the physical properties of the earth) proved these people wrong.
Science wins every time. However, politics and politicians are about power and control. Political philosophies allow politicians to practice experimenting on whole populations as they attempt to prove or disprove one political philosophy over another. You are right that socialism/communism have been tried and failed every time and, yet, there is always someone who didn't get the message that thinks they have a way to make socialism/communism work.
The big message that EVERYONE seems to be missing is this: Those who don't know their history are condemned to repeat it.