This creates inverted incentives: to take as much from the pot as possible while putting in as little as possible.
Same reason as why such communal systems never work if they get much larger than one family.
Inverted by whose standards? You could just as convincingly argue that capitalist enterprises are the ones with inverted incentives: to extract as much value from workers as possible while paying them as little as possible.
That doesn't actually change in a traditional capitalist system. The only difference is that owners and upper classes have more power than the individual to make their interest of getting the whole pot for little work happen
In capitalist system owner can enforce cooperation so the pot itself grows.
The proportion that workers capture here is of course dependant on external factors, like labour market and laws.