Well there is no "premise" to buy into with a hypothetical scenario, it's hypothetical. They split their resources out of fairness to all, since they couldn't all agree on a certain type of 'government' arrangement. Some wanted to be communists, some wanted to be capitalists, etc. I didn't say one guy had been successful, I said one guy was an engineer. He may not have ever been successful or made money in his life, but he knew how to make a coconut cracking machine and he knew this service would be in demand and capitalized. He also knew there would be a demand for seeds to grow food, so he took the initiative to develop the 'product' for trade and barter.
Now, if you were part of this crew, you might decide it best to give away the product of your efforts and labor, because there was a need from your fellow survivors, and that is awesome that you would be so generous and caring, but in the end, you'd be the first person to starve to death, because you didn't trade for food or supplies.