" Yeah, thinking that Nintendo would create a game which encourages enthusiasts to buy several versions so they can finish it properly is a completely unreasonable assumption. No highly-successful precedent has ever been set for that practice, and the gracious Nintendo would never pertain itself to such an unscrupulous act."
I appreciate any and all forms of sarcasm, but that doesn't change the fact that all the dogs are in every version.

And no one's making you buy all that. Trade with your friends, or be like me and only by one. I'm a rabid completionist, but I only ever bought and played one Pokemon game.