My initial thoughts is the end represents no trip into the past, that we are seeing alien intervention in Earth's time line, that this involves the Suliban, which has not been resolved, and that Earth has been transformed into such a sorry state of affairs it can never evolve and help create the future that we have all come to know and enjoy.
Earth is a pretty important planet, and if it never develops into the warp-driven society of peace and exploration, someone is not going to be stopped.