>>30692777>In XY it said that mega evolution is a new discovery, but ORAS suggests that it's been present for a long time.Well, first off, something can have been present for a long time without the scientific community necessarily being aware of it. After all, Rayquaza wasn't exactly hanging around in public too much, and legends are easy to dismiss as nothing but myth.
Second off, even in Kalos, it's been around for long enough that Korrina's grandfather is the "mega evolution guru," and there are legends about the first Pokémon to mega evolve being a Lucario.
The thing to remember is that, from the standpoint of someone studying it, the past 10 or 20 years is going to be "recent" in terms of a discovery. Compared to other topics of study, that means you're going to have significantly fewer sources to consult, and most of what you're doing is still going to be breaking new ground.