Elinor Ostrom proved The Commons can be collectively owned and managed. It's nothing to do with the scale being small or large if you actually read her research studies and the game theory models she published you would know that but instead you seemed to have use an LLM to frame your argument.

The main findings from Ostrom's research on the success of managing commonly owned pooled resources, and how the Tragedy of the Commons was wrong, is basically just enforcing audits, and retaliating against selfish individuals as part of a system of rules and social reputation. The other major game theory element is pointing out humans interact many times not just once, and that much of the original game theory models had arbitrary rules like players cannot communicate, or assuming the game only happens once, or assuming that the game cannot change or new players may join the game and punish the players that have been mismanaging social trust and resource policies.

"Conventional wisdom says that common ownership is a bad idea. “That which is owned by all is cared for by none.” Therefore, all scarce resources should either be owned privately by individuals or be regulated by central authorities. Or should they? Elinor Ostrom rejects that conventional wisdom. Based on numerous empirical studies of user-managed fish stocks, pastures, woods, lakes, and groundwater basins, she concludes that common property is often well tended."

There's a study of the grasslands in Mongolia, but that's just renforcing Ostrom's findings that the lack of auditing or policies for sustainability is what drives unsustainable behavior. Mongolia started to increase livestock and cashmere exports and their economy has not invested in modernizing or maintaining sustainable industrial scale livestock practices. Goats for cashmere has been a major source of income for Mongolian nomads but because they are essentially living out libertarian economics it's just more proof to validate the game theory factors Ostrom won the nobel prize for.

https://www.nobelprize.org/prizes/economic-sciences/2009/ill...

From the Nobel Prize website:

    Elinor Ostrom identifies seven keys to successful cooperation:
  • Rules clearly define entitlements.
  • Conflict resolution mechanisms are in place.
  • Duties stand in reasonable proportion to benefits.
  • Monitoring and sanctioning is carried out either by the users themselves or by someone who is accountable to the users.
  • Sanctions are graduated, mild for a first violation and stricter as violations are repeated.
  • Decision processes are democratic.
  • The rights of users to self-organize are clearly recognized by outside authorities`