I rather think it's people lacking the vision to foresee the problem, or ignorance on their part instead of the failure of capitalism. capitalism is just an idea, how you apply the idea into real world application is the art of it.
The promise of capitalism is everyone who has an idea, some asset, can make it big by combining resources in a free way, instead of having to be granted such opportunity by the central government.
the idea is sound and most of the time it works, however since human are often preoccupied with what is in front of them, they forget about longitivity - capitalism works best when everyone has money, when everyone has something new to offer - a blue ocean economy instead of a red ocean. But the fact is because of greed and insensitivity, third world countries are being stripped the rights they deserve, exploited, lower class income remain the last concern of employers, what you see now is the outcome of such misshandling.
capitalism does not nesscarily make people greedy, there are examples of people who give out a lot in building schools, helping charity, giving grassroot teenagers the chance - most of these people had experienced poorness in their early life and thus understand their personal enjoyment shouldn't be the top priority in their life, when they have so much power to make a difference.
successful business person often exhibit the character of being totally commited, putting result over method and generally being ruthness, that's why they screw things up at other's expenses, coporate responsibitliy is a fundamental chapter in business study, however it is a sad thing that most of the blightest people in the world think it is below their level.