Argument: Private property is not essential
Focusing only on the very narrow aree of Europe, the most prosperous time for ordinary people was a time without private property. This time was the 11th to 13th centuries. During this time there was no private property and everything was run by local currencies in local egalitarian economies (much of the aristocracy was losing control, hence why they invented corporations), not centralized currencies or large corporations. In Life Inc. Douglas Rushkoff writes that at this time "quality of life for most Europeans was better than at any other time in history, including today"; "The working class enjoyed 4 meals a day, usually of 3 or 4 courses. They worked 6 hours a day, and just 4 or 5 days a week"; "In addition to metrics such as demographic expansion and urban development, measures of health and well-being also surpassed our own".
This was the most prosperous time for Europeans in their entire history: it was also the closet Europe has ever got to socialism. But this prosperity was undone when, in the late 13th century, local currencies were outlawed, to be replaced by centralized currencies, and control over society was ceded to chartered corporations, owned by monarchs and run by wealthy merchants. Rushkoff writes that "within 10 years, the population increase had reversed to a decline as standards of living fell". This was the first attempt to impose something like capitalism (it was almost capitalism but not quite the one we know) on people and it collapsed in 1347 when the drops in living standards fell so drastically that there was an outbreak of what we now call the black plague, which killed more than half of Europe's population. The black plague was directly related to the drop in living standards that the introduction of the quasi-capitalism.