>>49354283>It's had been established beforehand that RSE occurred at the same time as RGB/FRLG so it's only natural ORAS would been before XYYou are missing the point, FRLG being compatible with RSE was contextualized as both games taking place during the same time period, and so became the case for HGSS.
ORAS being compatible with XY doesn't has this level of context, going as far as setting itself as a "parallel universe" to the GBA original because of the Megas. In essence, they either:
>A) shifted ORAS place in the timeline to be closer to XY than it was to FRLG>B) brought the Gen 1 events (the oldest in the timeline) closer to them as well (most recent in the timeline back then), effectively creating a loop and an excluse for yet another Kanto remake with MegasIn the end they picked a mix of both; Let's Go is yet another Kanto remake with Megas, but young Mina's cameo on it and adult Red and Blue's cameo in SM still show it's the oldest point of the timeline, but young Wally doesn't. (This without getting into the clusterfuck that is Let's Go's portrayal of Red, Blue and "Green" not as protagonists but as NPCs who didn't do the things they are iconic for but they oversee their replacements)
Case and point is that the Pokémon timeline was pretty simple and consistent before ORAS shat all over the floor with the multiverse.