Sony doesn’t allow Wildcard, the developers of ARK, to make their game available on PlayStation 4.
As the devs wrote on their forums, „As for the PS4 Release of ARK: Survival Evolved, it is currently up to Sony. We’ve been informed that we can’t release the game on this platform until it has been finished. We would like nothing more than to make ARK available on PS4 as soon as possible, as we already have an awesome PS4 version of the game running internally. If you would like to see it sooner, please let Sony know, as it’s unfortunately not our decision.”
Sony‘s decision makes sense from one aspect because they don’t have an early access program. (With Xbox, it would be Xbox Game Preview.) The performance of the Xbox One version of ARK: Survival Evolved isn’t the best, and that port has no final release date either.
However, ARK‘s situation brought up a good question: when will Sony create their early access system?