Ok Revenge of the fallen was 2 years after the 1st film. And Prime sent out a message to any autobots hiding amongst the stars.. So within 2 years that was said in revenge only Arcee. the Twins. and Jolt and Sideswipe came to earth.. So it must make you think others are dead cause of the war.. Or they would of came to earth within that time scale. So how can they add new robots for part 3.. Or will they try to explain how they came here putting in the phrase ohhh prime i got your message. Unless they are allready here hiding or are they going to get wheelie to find them old seekers
Others came that weren't in the movie, but featured in the prequel material (novels and comics) - Knock Out, etc etc.
But im on about the likes of Prowl ,Hound,Springer,Hotrod, Yeah just starting to read the prequel book. Longarm sounds like a cool autobot so far...
I also remember scene from the movie with Sams mom talking about Sam "popping his cherry recently" lol took him 2 years
Maybe that Autobots on other planets are held up because they are dealing with their own deadly onslaught of Decepticons. In TF2, it's mentioned that Transformers searched the galaxy for Energon resources, so perhaps some of them stayed to generate those resources
Space is pretty big and that message he sent actually takes time to get through space and then it takes time for Autobots to journey to Earth.
Unless Soundwave got the message and changed it like chinese whispers. Ohhh Autobots dont bother coming to earth we are ok.. Signed Mr Prime...
maybe they were the only ones within receptive vicinity, close enough to both recieve the message AND get to earth within two years. the universe is a big place, and frequencies take a long time to travel. wasn't there some massive delay between sending and receiving signals to an from the mars rover?(for some reason i wanna say it's two hours. or sic. or half an hour. maybe.) and if they're scattered amongst the stars.... stars are fairly far away.
that is probably the real reason but for peace of mind we can just assume that the message got out and arcee and gang were at a distance that took two years to travel to earth, maybe others are just further away and en route
Maybe the arrival of 3 new Autobots (Prowl, Breakway and Wheeljack?) can be jump-start of the movie? Like "Prime! We were captives of the Decepticons and they are going to attack Earth! We came to warn you!"