It seems to me that you define socialism as whatever it fails and capitalism as whatever it works.
Pure capitalism has never existed neither, so we have a spectrum of possibilities. I would argue that the better system is the one that improve the lives or the people and, that should be the measure.
Even if capitalism was the definitive answer, that doesn't mean that we should stop criticizing it.
If you have a system where, in the middle of the most advanced age of humanity, most of the people have not even the most basic needs covered, like was (and it's) the case of Venezuela, some criticism is needed.
I'm not going to argue that socialism is a good system, I agree with you that we have not good examples, but that doesn't automatically, leave us with a system where all resources have to be allocated by the market. In fact, if something has been proved for now, is that is a very bad idea.
So, when you criticism socialism, remember that a lot of countries in the world redistribute resources in a not market way very successfully. Call that whatever you want.
