For a number of reasons. BEWARE THERE ARE SPOILERS IN HERE --- 1) Jetfire is now allied with the Autobots and already sees Starscream as a traitor. I know this is tons of time before G1 starts, but he couldn't just forget about all of this that they went through. 2) Air Raid is dead. And so is Trypticon. I think I remember them both being somewhere in the G1 series. How would they just be brought back to life randomly. It wouldn't make sense. 3) Why would the Autobots be trying to revive Cybertron in G1 if they knew it was futile at the end of WFC? And why would the Decepticons bother sticking around there that long? They got what they wanted through poisoning the core. 4) Arcee is there from the beginning. Why would she just show up a long time later when she could have easily gone with the Autobots when the Ark was ready? There may be some holes in these questions since I didn't see the entire G1 series and didn't play the entire WFC game. If I'm wrong please correct me calmly and please no hostility.