I agree to some extent, but when the federal government is funding similar organizations with a similar mission, they have a strong incentive to work together. Public radio stations are operated and listened to by the kind of people who like NPR programming.

It's more like a federal employee who works for NPR and believes in NPR's mission donating to NPR. Yes, it's not compulsory, but the money is flowing towards entities with closely related missions that have a strong incentive to cooperate.

But again, I agree with you that the voluntary nature of the cooperation makes it quite different from merely some kind of shell game.