A game like Dreamfall isn't worth paying to make an exclusive. Both previous games were essentially PC only, so the entire fanbase is probably going to purchase the PC version anyway. Especially since it releases on PC before the PS4 anyway. Since the game is a continuation of the storyline from the previous games, it's not likely to be a game gets a massive influx of new players either. It's a niche franchise and isn't likely to sell millions and millions of copies.
Don't get me wrong. I'm a huge fan of the series. It has one of the very few mature and thought provoking storylines in video games, and the atmosphere is second to none. I consider both the previous games to be the pinnacle of the adventure genre along with Grim Fandango. I even backed the Kickstarter campaign to have it made. Nintendo just isn't missing out on much. It's primarily a PC game, and was designed specifically for the PC from the ground up. There is no point in paying for the exclusive rights to an inferior console port.