Technical merit, good management, and intelligent business deals aren't good predictors of success. If they were, and if those things were accurately and reliably quantifiable (which they must be to have any substance to them) then predicting success would be incredibly more common than it is.
The secret ingredient to success is pure luck. It's hard to swallow. If you disagree, then show me your billion dollar stock portfolio. The accuracy and reliability would only need to be moderately significant in order to extract obscene amounts of wealth from the market.
People who seem to be relatively good predictors of success, such as Warren Buffett, are incapable of articulating their thinking process. If they could articulate it, then there'd be many more copy cats. This suggests the possibility that the emergence of people like Warren Buffett is also a chance occurrence, and that whatever "it factor" they possess is entirely anomalous.
Hard work and fair play don't lead to success, they lead to marginal improvements in wealth and increasingly tolerable living conditions over long spans of time. That they lead to individual success is a noble lie we tell ourselves in order for society to extract those meager gains.
Now, hard work and fair play may lead to personal fulfillment. Maybe that's more important than any kind of economic wealth.