Although the Federation's GMs had been designed, built, and mass-produced for some time, their current stockpile was still extremely limited. Even after concentrating most of their MS for Odyssey Operation and assigning a smaller portion to other key strategic locations in space and on Earth, the number of GMs active on the Odyssey battlefield was still insufficient compared to Zeon's forces.
In the original story, the Federation's victory had been bought with tanks, artillery, aircraft, and the lives of Federal Army soldiers. Only then had they been able to cooperate with MS, bombarding the exhausted Zeon forces with artillery and missiles until they were destroyed. Yet even with four times Zeon's troop numbers outside of MS, they had fought for three days and three nights. That was still under the circumstances of Amuro causing trouble and killing people all the way from space to Earth, taking out quite a few aces. Now that Amuro, that ace, had not joined the Earth Force, those damned aces had not died either. That would make the Federation's situation even more difficult than in the original story.
Although the Federation had MS, their Piloting Skill was truly too poor to show off, especially without Amuro's combat data. The GMs' combat effectiveness was even more pathetic than in the original work. Against this important Zeon stronghold guarded by the Black Tri-Stars, the Federation should have assigned at least ten GMs to assist in the battle. Yet Xiao Ran had not seen a single GM. It was easy to imagine what those GMs had become at the hands of Zeon's MS: without question, burning heaps of scrap metal in the wasteland desert.
But Zeon's inexplicable large-scale MS deployment at Odyssey was also one of the fundamental reasons behind the Earth Federation's disadvantage. Xiao Ran had never