I would not be surprised if S-E took a look at the sales of Prey and just threw in the towel altogether. I don't know what's changed in the years since Human Revolution and Dishonored 1, but sales in this genre have just tanked.
Well for both Prey and Deus Ex MD, a lot of potential sales were sabotaged by the inept decisions of their parent companies, and the games suffered as a result. They won't acknowledge it was their fuckery but both SE's shit tier preorder hijinx and subsequent delay and Bethesda's shit review copy policy hamstrung both games. In neither case can they say they put everything behind those games to make them succeed and the public just didn't care. Both were essentially sent out to die.