It seems in this show everyone knew about the original primes (their names, their weapons). But, I feel like given the context we were given about Optimus's past. Did no one know Alpha Trion was a Prime?
As far as we know, last I checked... the only ones who could know where the other Primes themselves. Optimus seemingly lost that information when he willingly chose to enter the Well. Smokescreen (who was also described as being quite close to Alpha Trion) didn't seem to know either. He told Smokescreen how me made Orion Pax a Prime, but I don't think he ever brought up how he and Orion are both members of the thirteen.
So, basically Alpha Trion purposely kept that information secret and somehow the knowledge of it didn't exist; even though the knowledge of all the other Primes (except Thirteen[bc he was reborn]) was public knowledge? I wonder how he did that.
He quite literally controlled the narrative. He was the author of the Covenant of Primus and he was the one who redacted Optimus' name from it. Some of the Primes were more prominent than others as mythological figures, so the knowledge of them persisted throughout the ages, but Alpha Trion pretty much controlled all of the first hand information about the Primes.
Afaik Trion himself, as the scribe, never did much to make his own name well known until after he’d dropped the ‘Prime’ epithet. So no one remembered him as a prime, the other twelve were dead, amnesiac, or otherwise out of the picture, and he wasn’t about to tell anyone.
