It just takes longer to notice its failure the more successful the society it is tried on. If the society has great wealth and good infrasture, it will take decades before you “start running out of other peoples money” and the infrastructure starts to decay.
So in that sense, socialism is similar to a long acting poison like lead poisoning.
Socialism it alive and well today. Those who rely on the government for their welfare are radically poorer than those who rely on some sort of market based welfare, regardless if the market it supported by the government, or private industry or some partnership of the two.
Look at any big city in the US. But most big cities have a long way to go before they hit bottom. Some will get there faster than others.
screw them