I think it often boils down to this: people who have more resources are allowed to test their luck multiple times, fail and try again until they succeed. People

I think it often boils down to this: people who have more resources are allowed to test their luck multiple times, fail and try again until they succeed. People who don't have resources (a large inheritance say, no college debt) even if they are smart, might only get to try once. Invest their time, energy, money into one venture, fail and they could be screwed. So in other words, looking back a particular instance of success might look like luck, or a coin toss. But some people just have more coins to flip than others. You can also factor persistence in there as well, and make not just about money. Say those that fail have enough stubbornness to get up, get to toss the coin again, and again. So perhaps sometimes the limitations are self-imposed not just external resources that are limited.