>>49209719fossilmons were extinct until, surprise, we brought them back to life or traded them into regions where they had no other way of existing
the games have 0 concept of canon or continuity, all it takes is 1 new game to have any given pokemon running around in the wild despite previously not being alive
besides, the game is considered part of the core series by nintendo themselves, dipshit. its not a spinoff like mystery dungeon or rangers. legit just confidently correct about something so easily googleable