So this is the the supposed timeline for how each of the games take place. This can lead to a lot of things. Such as the idea of Kanto sequels, and how exactly they would fit in (mentioning because it's been brought up a lot recently) People would much rather have sequel games instead of just complete remakes. There's more story to be told in Kanto, and what else but a sequel. But how would that fit in? Would it be set in the current time with megas, or would it be only a very few amount of years after the originals/remakes - which is technically a time without the discovery of Mega Evolution. The question remains.

Also something I realized that I haven't seen said before personally, is the concept that Sun and Moon takes place in the timeline sometime prior to where X & Y is but is sometime after Black and White 2. This would mean that it's before Mega Evolution is a thing, meaning that Alola doesn't know much of it if any until the post game. That way we'd get Megas in the post game when they're finally gaining knowledge about.