You have not known truly free markets. You HAVE had "some" form of Capitalism.
It's quite simple...
Capitalism follows human nature much better than any other system. People typically think of themselves first (self preservation). It then radiates out to Family, extended family, friends, town,state,country,globe. But the person in the center is the individual person.
Human nature also dictates that like Pavlov's dogs, humans like to be rewarded and will follow patterns which lead to rewards. In today's world that can lead to many things... love, money, respect, partying (woohoo!).
In economics however, it is accumulating wealth. Some ppl are satisfied with not much wealth, others want much much more.
But typically wealth just doesn't descend down upon you like raindrops in a spring shower. You sometimes have to take risks and work very hard to build an opportunity to get your reward. If you succeed, you should be rewarded. If you fail, you must learn your lesson and reset.
Capitalism is the best vehicle for allowing the MOST ppl to have access to taking risks (informed or uninformed) for receiving that reward.
Socialism does not. Communism, it is practically non existent. Certianly, not within the individuals control.
That's the last point. People like to feel as if they have control over their lives. Capitalism again for the very same reasons gives the MOST people control. Most ppl who don't control their lives in the USA have given up that control on their own. No one has taken it from them.
Socialism/Communism don't work with those parameters. The entire premise is that the State can do better than the individual. Never forget that Europe never had a flourishing democracy in their history. They visit us, but that's as close as they can get to it. They have gone from Old World Monarchy to cataclysmic wars, to Socialized Democracies.
When people have control and are allowed access to markets so they can apply their trade and get their reward, they are made happy. Happy people are a productive people. This is one of the reasons why the USA consistently outperforms other nations. And so, in that reward system which is very accessible, ppl are made happy and productive. They can take care of themselves, their family, friends, town, state, country.
Des it work that way always? No.....
That's because this entire process involves humans with all of their quirks, foibles, and faults. it's an imperfect world. We are imperfect beings. Capitalism is imperfect.
But it's a hell of a lot better than any other system. by far.