Terra In The Original Timeline Was Completely Destroyed

When Thomas Aldous Rawling was discovered to having been impersonating the youngest Atreides prince, after having murdered him to effect that strategy for world domination, he launched a never-ending stream of criminal robots that completely sterilized the original human homeworld of living beings. Those robots spread out, and completely wiped out all the living beings throughout the rest of the universe. There were no survivors. No one escaped, because they would have essentially had to time travel in order to do so. Only robots capable of transporting using wormholes themselves escaped.

In order to have even one living being from the original timeline of the universe, William Atreides of Terra and Andor had to literally be resurrected, and he was chosen to be resurrected because of the relatively unique circumstances involved in his death, and the conditions of his very short life before being killed.