CD Projekt Red has sold 20 Million copies of the Witcher 3 as of June 9th 2015 ,your beloved CD Projekt red is trying to Maximize profit, it isn't anything that they're doing "because of the fanbase", EU IV has sold one million copies as of the 21st of June 2016 ,it has a smaller market aswell so take that into consideration , The Witcher 3 doesn't get constant free updates that change the game and add new stuff to it as a whole (i know there are small portions of the game that have nothing do to with the main game that still get updates (Gwent)) ,EU IV being developed by a smaller studio , constantly getting updates that upgrade the game beyond release day quality unlike many AAA games everyone here keeps comparing it to for some reason justifys the price staying the same , since as you may know Paradox has a dedicated team working on EU IV at all times , a game we all love is given love because this dlc policy exists ,everything has a reason and there are things that wouldn't be available to us the consumer if it was any different.
Also the replayability of EU IV in comparison to the Witcher 3 makes it worth it and i do not understand why everyone keeps comparing the 2 since they cannot be compared is everyone stupid or what?