A sharing economy is any economy in which there exists no monetary form of exchange, and the people trade necessary goods and services based on common goodwill, sometimes barter. For example, a group of hunters will go and hunt for everyone sharing the results of the kill with nonhunter females and male and female children/elderly.

Money is not real. It does not exist. This was true in the past but is even more so now, since 99% of all money is just keystrokes on a central banks computer. Money was invented as a tool of slavery and control, nothing more. When food grows out of the ground, and water falls from the sky, why would you need money?

In general people do not share in this day and age. Everything has been 'monetized'. In many countries, even using a bathroom costs something. Greed before the creation of money certainly 'existed' because it exists now and it cannot be said that money created an emotion that didn't exist in the past. However, greed was highly disadvantageous to an individual because without money, there is no way to be truly greedy.

Sure you can eat the last banana out of greed, but you can't eat ALL THE BANANAS out of greed, because your stomach has finite space, and your body a finite appetite. But with money you can BUY ALL THE BANANAS and let them rot just to spite others and prevent them from eating. This is a level and aspect of greed that was not present in the past.

You can find a successful implementation of the ideal/non-ideal sharing economy in any non-western tribal society, hunter-gatherer society and any group of people who live together and survive/thrive without the use of money. There are much more than you realize.