The foundational flaw in collectivist economics is trying to compress decisions normally made by millions of people into decisions made by a few. Who decides what contribution someone has made? And to who? By definition "value" is decided on an individual case-by-case basis.

The concept of trade depends on this. Something I have is, at a given moment, less valuable to me than something you have, and vice versa. We make a deal, and against all logic, both of us come out ahead in our own minds.

These valuations can change constantly, depending on the circumstances, the people, the place, and many other variables, which is why prices vary and supply-and-demand works.

In short, any universal rule pertaining to productivity and reward is doomed to failure.