If Shockwave, various other Decepticons (including - Three unnamed seekers, one later named Sunstorm, the other two unknown - Ep: Divide and Conquer) and the Autobots (Female Autobots: Chromia, Firestar, Moonracer, Elita-One. Male Autobots: Alpha Trion) were all on Cybertron four Million years after attempts were made to obtain a fresh supply of Energon - Otherwise "no-one is going to win this war" - Optimus Prime, then how did the Autobots and Decepticons On Cybertron still function for so long without a power source? If they had enough Energon to keep going long enough to establish contact on Earth then what was the point in the desperate mission to find fuel if they had four million years to find other options? Personally, I prefer the comic book explanation where a meteor storm threatened Cybertron, forcing the Ark to be launched. It certainly seems more plausable in retrospect.