A testament to how insanely popular Pokemon was back in the 90s. Even Pokemon Go's popularity is nothing compared to how big Pokemon used to be. Everyone tried (and failed) to make a Pokemon clone...that is, until gacha girl games was invented and stole the throne from Pokemon!
Technically, this is expanding on the mechanics of Dragon Quest 5 which never came out in the West until the DS, and DQ5 predates Pokemon by about 4 years