The baby of Madelyne Pryor and Scott Summers did get infected with the techno organic virus and was sent to the Askani controlled future, but the Askani in the future are actually the descendants of Rachel Grey and Franklin Richards, who become the Eyrie of Warlord's future Earth. Baby Nathan Summers of the Askani future is cured of the Techno Organic virus, trained by the Askani, and then jumps back in time as Rama Tut to prevent Apocalypse from coming to power. Nathan Summers is actually Kang and Cable is actually the son of Nathaniel Richards (Reed Richards's dad.) Nathaniel Richards, a time traveler himself, must have know about the importance of Baby Nathan's fate to kill Apocalypse so he raised one of the sons he bore in Otherworld and conditioned that son to believe that he is actually the Nathan Summers fated to kill Apocalypse. Any of Apocalypse's agents would then seek out Cable, and not Kang, thus protecting the prophecy of Apocalypse's defeat. And since Cable is from future Otherworld he doesn't know necessarily future events after a certain point when the future earth in Warlord diverges. And that's why Cable can time jump freely because he actually originates from the Otherworld dimension and Bishop couldn't travel back until after Cable defeated Ahab at the Temporal Nexus.