>>23195367The same way GSC exists in the same universe as games where Dark and Steel types don't exist (RBY)
There are many universes, with altering events in each. There isn't just a Mega universe and a non-mega universe, things aren't that simple, there will be differing mega universes and differing non mega universes. You'll have mega evolution universes which are incompatible with other mega evolution universes, and the same will apply with non mega universes.
In that same vain, some mega universes will be compatible with the events of previous generations(XY), and others will not(ORAS).
You see in XY, you will find that the introduction of Mega evolution and the Fairy types were treated they same way as it was in the anime, new discoveries which were at that time, were known to only be limited to Kalos, Sycamore even says this in Coumarine City.
""It's only a hypothesis, but I think the bond between Pokémon and Trainer is the key to this new Evolution. But what is this bond, exactly? And why are there examples of Mega Evolution only in the Kalos region? There's still so much we don't know..."
His line about examples of Mega evolution only being in Kalos is directly contradicted by ORAS, which is set at least 5 years before events of XY and where Mega Evolution is already well known. Not to mention in XY, we are told that Lucario was the first Pokemon to Mega evolve, whilst in ORAS it's Rayquaza.
XY and ORAS share one similarity, Mega evolution and Fairy type, but that is where it ends, they are incompatible, unless someone wants to tell me that everyone in XY was a dumbass and didn't know about Mega Evolution and Fairy types had existed years before,
