Since the TF board is about as dead as Atari is, I figured I'd post this topic here.
Okay so Optimus Prime becomes the leader at the start of the Decepticon uprising and had the power to face Megatron. Okay so I can see him being considered the savior of the Autobots at this point.
Now then.....just how long did the war go on?
Well in the old cartoon, it went on for 5 million years at which point Cybertron is a wreck and its resources nearly gone. Optimus leads a mission to get new energon resources, they are intercepted and they crash on primitive Earth and lay dormant for another 4 million years.
Meanwhile, the war still grinds away on Cybertron in the old cartoon. Shockwave for all his power couldn't conquer the planet and apparently no one could step up to replace Prime. Where was Ultra Magnus?
earth year 1984, The TF's on Earth get reactivated and the war carries over to Earth for years.
By Earth year 2005, the Decepticons have won and taken the planet. Who knows how many Autobots were terminated in the process. Optimus is reduced to bases on each of the planet's moons and Autobot City on Earth.
Optimus was preparing for a final offensive to retake the planet and defeat Megatron when he had to go to Earth and make his great sacrifice in battle against Megatron.
Unicron attacks and Rodimus Prime arises and what does Rodimus do? FINISH what Optimus couldn't do.
1. Destroys Unicron.
2. Leads the Autobots and the Junkions to retake Cybertron in the confusion following Unicron's assault.
3. Over the course of a year Cybertron has been refortified and can repel any attack by the Decepticons who are in exile and dying until the Quintessons come for them.
Cybertron was slowly rebuilding and becoming more energy self sufficient under the command of Rodimus, who while compassionate and caring was able to make hard choices that Optimus couldn't such as blowing up a planet to keep its energon away from the Decepticons.
Optimus led his people in a war that he couldn't end for millions of years. He should have been replaced sooner.
Optimus is usually too optimistic. He has plenty of chances to finish off Megatron or win the war over the years, but never takes them. His optimism misguides him to think he can still reason with Megatron. The result is needlessly prolonging the war and more death and destruction. I have seen this outside of the G1 and in other versions of the character. I think that is one reason they made the film version of Optimus more ruthless. He is supposed to be more realistic and jaded by the war.
At the same time Megatron is no better or possibly even worse. Depending on the incarnation Megatron is either an ex-gladiator or military leader who is willing to cross mortal lines that impede Optimus. He is supposed to have the ultra-ruthless and powerful warriors. Yet he can't defeat what amounts to a peaceful scientist and a bunch of civilians. He won't even scrape Starscream despite all of the latter's betrayals. Even the scenarios where he pretty much wins the war he has lost so much it is a Pyrrhic victory at best.
Optimus is pretty much the perfect leader for peaceful times. Less so in military times. Megatron though it just incompetent all around.