Crytek Explains Why They Are Not Bringing Ryse Son of Rome To PS4

[forevercloud3000]

The reason is obvious....
Although Crytek still own the IP they more then likely have a contract clause saying they cannot release it on the immediate competition(PS3/PS4) ever or with a certain time limit. Crytek was dissatisfied with sales so they are trying to milk all the money they can before plunging into more dev cost by releasing it on PC.

Only some kind of contract obligation would be keeping them from putting it on PS4 at this point.