Bernie Sanders believes that things can be produced in an economy, even if no one produces them. That same view motivated the late Hugo Chavez.
The essential idea is that a society's wealth and production is simply a given. It doesn't really depend upon anything. Wealth and production is simply there for all to divide. Thus, the policy prescriptions that follow are pretty simple (and obvious). Divide the wealth and production equally. Since no one produces anything, according to the Sanders-Chavez view, why let the wealthy folks keep anything?
This argument plays well to poor folks and the affluent young. You can see it in the Sanders support. If you polled the wealthy, elite colleges in America, Bernie Sanders would, far and away, lead the polls, just as Chavez was extremely popular with the wealthy left in Venezuela.
If you are born with a silver spoon in your mouth, it is never exactly clear how that spoon got there. You didn't put it there. So, why can't the poor share that spoon. The argument is very appealing to young people who never saved or sacrificed to produce wealth. They simply woke up one day and found the necessary resources right there in front of them.
The problem is that someone needs to produce the wealth and provide for the production. In order to do that, incentives have to be structured to encourage the necessary work effort and personal sacrifice required for the creation of wealth and the production of economic goods and services.
The Sanders-Chavez (and indeed Clinton) program is to eliminate the incentives for wealth creation and the production of economic goods. They view these incentives as evil -- the word "greedy" comes to mind.
Instead, the Sanders-Chavez-Clinton agenda is to remove individuals from the consequences of their actions. Big government will provide. The problem is: who will provide the resources for big government if private incentives are legislated out of existence?
History provides the answer to this puzzle. Revisit the old Soviet Union. How did people live, once the government stripped away the incentives to produce and outlawed the holding of private wealth? How are things going in modern-day Venezuela (or Greece for that matter)?
Once those who make the necessary sacrifices to produce wealth are viewed as criminals, it is only a matter of time until the country degenerates into a Venezuela situation. Then only armed forced, as used in the old Soviet Union, can maintain the Sanders-Chavez-Clinton paradise. Venezuela is a glimpse into the future of the Sanders agenda.