A good write-up, Matthew. Original, and I like that.
The one part that you did not investigate is the surrounding reality of the two individuals involved in the game. There never was and there never will be a reality in which two people are all there is. There is always a surrounding context.
Let me make this more clear with capitalism and the political system in place.
Capitalism in China will have a context that is distinct from capitalism in the United States. In China there is a single governmental structure (otherwise containing many complexities) and no entry to influence this unless as a member of the Commu-capitalist Party.
In the US, there is a context of voters being able to influence the capitalist reality. Often that influence has its limitations.
Contrast this with a capitalist nation where there are six parties. In those nations, the voters have a greater chance to influence the capitalist reality because the parties are not based on the winner-take-all format, but on full-representation. Meaning: all voters end up with their representatives.
So, while I enjoyed reading your article a lot, I hope you agree there is a context as well that has tremendous influence (partially so by blocking certain influences). In light of capitalism, and the data confirms this, one can better live in a nation with five parties than in a nation with just two or even with just one party.