Great point.

I will add two levels of nuance.

One is the extent to which individual future donors are necessary.

The other is the divergence between any group's goals and those of its members. A good analogy is heat dissipation: for any one member, one can't predict his or her goals from the group's goals, though in general one can generalize about group members and their goals.

Note that these are matters of extent and not type. Note also how much this is true for other things. :)