And the alternative is? Communism? Nice idea, but it has been shown to fail by history. You said to look at history, but if you do, you see that most of the world has been capitalist for a long time, and it has worked out pretty well so far. Yes, you get depressions, but you also get highs, one tending to follow the other.
Human nature has not evolved to share. It has not evolved to look for the best for everyone else, it has evolved to look after itself. That is why communism fails, even though, in an ideal situation, it would be the perfectly fair option. People suffer regardless, but you cannot say that there are more people suffering in the UK, USA or EU than did in the USSR.
Man will never fly. Space travel is merely a dream. All aspirin is alike.