Honestly, with how things tend to go here, it would probably have something to do with the bonds between humans and Pokemon and what have you. The regions... they seem to resemble parts of countries rather than countries themselves, but given that the closest thing they have to a government is effectively a sporting league, who even knows?

[...the absolute pits...]

...I may. I believe I would have to deal with everything else first, though, and it'd be just my luck if they were stronger than expected.