What if the crew failed?

Suppose Admiral Kirk and his cohorts failed to bring George and Gracie into the future, what do you suppose would have happened to Earth and the Federation?

*Nothing; another ship or some uptime agency will eventually figure it out and pick up some whales.

*Nothing; the probe will eventually give up and leave.

*Earth will be destroyed, but the Federation will carry on with other members.

*Earth will be destroyed, and the Federation will break down.

*Something else... (Specify)