But of course, when remakes do happen it's generally safe to assume they're the "current canon" they'll reference moving forward, in case something new comes up within them.
Ultimately, I think if GF want to reference something from a previous game, they won’t really worry too much about which “timeline” or “universe” it’s supposed to be in. If they’ve introduced something in a main series game, that’s just part of the canon now and they can invoke it as they please.
In one sense, that does make it very simple to interpret the newest remakes as the “current canon,” because they retain mostly everything from the originals and anything that a remake or sequel adds
also becomes fair game, so I get
why people do that. But at the same time, I doubt that GF would ban themselves from making a Kanto sequel game with NPCs who referenced, like, Pikachu’s Beach
and the Sevii Islands, even though those features are from what fans commonly designate as “different timelines.”
Taking Mega Evolution as an example, I truly don’t think Game Freak care if, like, Sword & Shield “take place in the Mega timeline” or not. Mega Evolution isn’t in those games, so it makes no real difference, and like you were saying, similar events probably play out in any reality
regardless. So the lack of references to it in Sword & Shield, or the oblique references to it via Roaring Moon in Scarlet & Violet, don’t really strike me as something to read very deeply into.
When Sina walks up in the Alola games and is like “It's so mysterious... to be talking about Mega Evolution here, in a region so far away from Kalos...”, a lot of people read that and immediately think “Aha, so this game is in XY’s universe rather than ORAS’s, because what she said could be construed as Mega Evolution being a Kalos-only thing like XY suggested.” But I um… I don’t really think they were trying to say all that. Mega Evolution was introduced in Kalos, Sina’s from Kalos… she’s just referencing that stuff generally.
And then look, fast-forward to Legends: Z-A, which is an explicit sequel to XY and references the Mega Evolution lore from both of those games, with multiple acknowledgements that the phenomenon actually originated in Hoenn. And this game
also has the Hisui exhibit at the museum showing that Legends: Arceus happened in this chronology, but that game itself set up Giratina’s role in Platinum which people tend to consider part of the “non-Mega timeline,” and it’s just… these timeline differences really don’t mean much of anything beyond how they inform the last third of the plot of the Delta Episode.
(And
even then, USUM showed that there are in turn multiple offshoot realities of “non-Mega Hoenn” since Team Rainbow Rocket’s Maxie and Archie have their original designs, don’t use Primal Reversion, and don’t come from the same parallel world as each other, so it’s like, “Which non-Mega timeline Hoenn is actually in danger in the Delta Episode? Ruby’s or Sapphire’s or Emerald’s?” We are able to intuitively compress the equivalent canonicity of
those games; we should be able to do the same with original games and their remakes.)
Aside from Let's Go. That one feels...like they probably won't keep that one from overwriting anything.
I agree, though I also wouldn’t be surprised to see Let’s Go get mentioned at some point, implications be damned. Like maybe Blue shows up and says, “You know, you remind me of a couple of Trainers I met back home. Watching them take down Team Rocket sure was something!” You know, the kind of thing that would instantly spawn a hundred YouTube lore essays about what this means for the
~timeline~ but is really just supposed to be a cute nod to an old game.