While capitalism does have its weaknesses, it also seems to be one of the driving forces behind modernity, which I think most of us can agree is a supremely good thing.
We've tried tearing down the system before. Communism failed, not because of failed implementation, but because the concept itself is a bad one. This is not to say that we should close ourselves off from thinking of new ways to organize our societies, but it seems that capitalism and all that it encourages is responsible for the 'rising tide' of global human civilization we've witnessed over the course of the industrial revolution to now. Sure there is inequality, but as they say, a rising tide lifts all boats. Would you want to be the average middle class or poor person 300 years ago, or today?
As innovation continues to change the material conditions of the world, our economic systems will evolve in response, probably for the better. Capitalism will not look the same in 100 years or 1000 years as it does today. But over time gradual development will improve the system, not some grand scheme that calls for tearing down capitalism and replacing it with something else.