Well, I for one saw Optimus Prime during beast wars.... he was in the ark with Megatron trying to murder him... so there hehehehe okay okay so they went back in time but still he was there

and as for Rodimus, that good for nothing leader as far as I know, went "away" on self exile with kup in tow and didn't even bother to hand over the matrix for pete's sake! How Selfish! good thing the next autobot leaders didnt need the Matrix and were quite powerful and deadly on their own - Dai "killer" Atlas for example.