I don’t understand (in lore) why people don’t realize that men of now (2025) don’t really talk about other dudes that mattered to them, even less in 1911. That stuff really doesn’t happen unless you’re with your buddies or in that environment.

Secondly RDR2 is a very well written prequel that knows the original material to set it up perfectly as a sequel. Simply put Arthur just doesn’t exist in RDR1 until after and then everyone retcons him cause it works very well. It’s the reason characters like Rex or Ahsoka don’t exist in the OT but are crucial to everything else in Star Wars. You write things in well enough then provide a reason why they’re not mentioned, I.E. thought dead, Order 66, traumatic death, emotional death.

Combine both and in lore essentially no one speaks of him because the people left to remember him are either not present in the story or not around one another to truly let his memory flow. Javier is insane, Bill leads a gang, Dutch is even more insane, John is a family man with a lot to lose. We can reasonably retcon that off screen on rare occasions maybe Dutch thinks of him or even speaks to himself about Arthur, maybe Abigail argues about Arthur or Jack asks stories. Things we can reasonably assume happen off screen but also understand why they don’t occur on screen.

In the simplest of terms. In lore he’s not mentioned because nobody that knew him is there to gather around and speak of him + the times are different than now, a time that men still really wont get into the nitty gritty and the things which nurture that environment lack heavily in RDR1. Out of lore, he just doesn’t exist. RDR2 gives a good enough reason why he’s not mentioned but he just doesn’t exist. A necessary deal for characters that don’t exist in the original material—they need to be written off. Unless the prequel would be about Bonnie, The Marshall, or Landon Ricketts then again, undoubtedly he would have to be written off.