If you give 20 people 1 dollar each and then lock them in a room for a year, when you come back you will have 1 person with $19 and 19 people fighting over $1.
Another example: one of our earliest colonies was completely socialist and completely failed...there were not enough people willing to work to ensure the survival of the entire colony. Those that survived rearranged the framework and it became every man for himself. The colony not only survived but thrived.
Democratic socialists like to dismiss the human nature aspect of socialism, but human beings are what they are and if they have no incentive to prosper, they simply won't. Hope (aka capitalism) on the other hand is quite powerful.