EA never released a full game for the 18 World Cup. it's just a DLC for FIFA 18 with stadiums, updated kits, a couple of qualified teams that weren't there in the original game and, of course... Loads of FUT content.Is fifa 18 WC a separate game to fifa 18? Or a patch?
This is the way it works lately, unfortunately: either EA and Konami don't feel like releasing full-fledged games for these tournaments (Euro and World Cup) anymore. They just release themed DLC's so they could push more "special" MyClub/FUT content upon the users.