However when we are talking about a reality in which there are multiple independent and competing launch entities, the idea of "the earth" as a single entity capable of deciding not to service colonists makes much less sense.
The whole point of Galt's Gulch is that the world is corrupt and evil and the Randian heroes have to establish a self-sufficient colony where they can support themselves, and stay there until the evil altruistic world collapses under its own weight. That's rather opposed to the concept of having to import everything.
