But sure, lets praise capitalism!
This is demonstrably false. Extreme poverty was simply the state of the world until a few centuries back. In 1820 more than 90% of the world was living in extreme poverty.
It's absurd to claim a single diffuse concept like capitalism was responsible for lifting people out of poverty, it's just as absurd to claim it was responsible for putting them there.
Alternate systems have not worked out so well, as you know. Communist planned economies led to the starvation of tens of millions, and that number increases to hundreds of millions when you add the persecution, jailing, and sometimes immediate execution of citizens of Communists states that had a history of political activity of the wrong sort. Recall that in Soviet Russia it was beneficial for each individual to "inform" on their neighbours to the KGB, so that they could claim their apartment. And it's suspected that Vladmir Putin is actually the richest person in the world.
Colonialism and slavery are pretty rough, but they are not a product of capitalism as much as a product of human malevolence and brutality. I'm sure you would find evidence of colonialism and slavery in pre-civilization times and in non-capitalist societies, so that argument falls flat.
Also, regarding the 8 richest individuals - If the rest of the world is getting on OK, why should we not have a couple of super rich people around? Why is that inherently bad? Why do _you_ think you should have a say of where that money belongs, exactly?
Why is that not a product of human malevolence and brutality?
I'm sure you would find evidence of persecution, jailing and sometimes execution of citizens in pre-civilization.
Imagine I want to send a rocket to Mars. And then I go and check the prices and see these companies want hundreds of millions of dollars to launch one. That makes me confused. The materials to make that rocket cost at most on the order of tens of millions of dollars, and labor certainly doesn't explain the rest. I bet I could make one for less. And it turns out I can. Then a couple of decades later, I'm the biggest rocket supplier on the planet. In a communist system your only option there would be to try to appeal to the bureaucracy, and if you're lucky you might eventually, some years later, get a reply to your filing of form FNE-34821.43-z: 'We disagree. Thanks for your input, comrade.' Of course this probably isn't a fair comparison. In a communist system nobody would ever have the resources to even dream of being able to do something like launch rockets to Mars. Instead you'd have to beg old entrenched government bureaucrats to do it. I'm wouldn't hold my breath.
This notion of an economic system being driven by the people instead of being driven by the government is why in a capitalist system you're generally free to argue for a communist system - with some unfortunate exceptions, yet in a communist system arguing for capitalism is often enough to get you 'disappeared' - with some fortunate exceptions. Maybe even more visibly in a capitalist system you could even start a communistic system. Want to buy 5000 acres of land and start communitopia? Feel free to! Want to buy 5,000 acres of land and start capitalitopia in a communist nation? It's simply not possible.
And we also saw this exact scenario play out in space. We never really managed to bring space to into the capitalist system. And once the government 'won' the space race, their interests shifted from space. Not only did progress halt but we technologically regressed. We put a man on the moon in 1969. Today, half a century later, we're struggling just to try to send a man around the moon - let alone land on it. No human has left low earth orbit since 1972! But at the same time space has now been genuinely introduced into the capitalist system and so long as the people have a desire for more, the odds of us entering into another 50 year regression are rapidly approaching 0.