I think people are honestly going to start getting tired of graphics being the only new thing these two are bringing to table.
Once you get past PS4/XB1 IMO, you reach a level of graphical fidelity that is good enough for many people.
That's why PS4 Pro is not impressing consumers ... it's just the same games that look about the same, just shinier. Most people don't care.
Not a lot of people are going to want to buy an entirely new TV just to get 4K graphics either, and I'll be honest the jump from 1080p to 4K is nowhere as noticable as the jump from square-box SDTV sets to thin HDTVs.
I think Sony should sit back and wait. VR is far more interesting, work on developing that.
I would not be surprised if you hear nothing on PS5 until 2019 and no release until 2020.
