This note is a part of my Zettelkasten. What is below might not be complete or accurate. It
is also likely to change often.
If you think of it rationally, groups of individuals with a common interest are expected to act to further their collective goals just as individuals are expected to act on their personal (even selfish) welfare. Unless the number of individuals is quite small or unless there is coercion or some other special device to make individuals act in their common interest, rational self-interested individuals will not act to achieve their common or group interests.
This difficulty of getting individuals to contribute to their joint welfare was illustrated by Mancor Olsen in his 1965 book "The logic of collective action".
This argument is related to the Freerider problem.