Capitalism is the extraordinary belief that the nastiest of men for the nastiest of motives will somehow work together for the benefit of all. - John Maynard Keynes
While still flawed and ultimately pale in comparison to socialism, his economic vision was still light years better then the utter dystopian hell we have entered.
Yeah, this is not definitely attributed to Keynes, and earlier verions of it by other people paint this in a slightly different way as a positive point, that even nasty people work for the benefit of all. Many versions have been attributed to Keynes, both as a positive and a negative for capitalism.
Competition is key. If they work together, it's to the detriment of all.
The problem of capitalism is that managing the competition becomes too complicated. Additionally, competition leads to price distortions. That can also become problematic.
The beauty of capitalism is that it rewards cooperation which makes it ugly because the lack thereof shows our deepest rifts.