>>55185230There are NO patterns. The only thing I know for a fact is Game Freak and TPC like selling merch to kids. It's one of the most lucrative aspects of this franchise. And kids need to know what "a Johto" is whenever they head onto Amazon or into a Pokémon Center which have toys arranged by region of origin.
So they need to keep the region and it's characters fresh in the minds of children via the main line games. And at the end of the day, money always wins. You literally cannot argue against this, it's bulletproof reasoning.