>>40769989Goes a bit deeper than "just use new ones". People who have invested time in the series have collected a shitload of Pokemon over the years, either from just playing the game casually or through breeding/injecting. Like this guy here.
https://imgur.com/gallery/Cc20H#IHL4m8DDude made a whole guide on ribbon collecting on the Colosseum Delibird all the way through Gen 7. Thankfully today it was confirmedto be, but I consider that lucky for now. Game Freak/TPCi/Nintendo decided to chuck that all out the window to make the games exclusively to those who play through the game once and then get rid of the game itself so Game Freak could keep to the one game a year schedule.