This thought experiment is based on an unrealistic view not only of natural history but also of the human condition and modern economics. It is based on a view of how easy the perceived human condition was before the existence of larger society.

"In prehistoric times our deal seems to have been not so bad. During the Old Stone Age (50,000 years ago) we were only few, food (game and plants) was abundant, and survival required only little working time and moderate efforts."

This period of hunter-gatherers was largely the experience of 90% of the time looking for food. It was only the emergence of sustained and coordinated agriculture requiring public works that this started to change. Modern industrialized agriculture has enabled populations not sustainable in that text and requires a larger coordination of people than a small commune can support. That text does not cover larger governance and relies on high-output lands to sustain itself, let alone others. If you cannot enable specialization, you cannot scale nor can you provide the lifestyle people are accustomed to enjoying post-WWII.

There are already communes like this everywhere and nobody is saying that you cannot start one. The only issue is people trying to force others into this system. It starts based on oppression regardless of feasibility.