1080p is a thing of the past, wave goodbye to your tiny 20-40" screens; we've seen the future and it's 4K. In all fairness, we've not seen anything and the price for a 4K display, containing four times the pixels of 1080p, won't be sensible for quite some time yet, yet alone widely supported. Even so, since Sony are so keen to push the idea of 4K it wouldn't make a huge deal of sense for them to completely ignore the idea when putting together their new console.
This means one of a couple of things: either the PS4 won't come out until graphics cards catch up and become cheap enough for use in a home console or there will be a re-release – a PlayStation 4 Slim, if you will – which will feature support when it becomes viable. It's a choice between screwing over early adopters or delaying the whole project.
There's always the chance that it'll be ignored completely, but it's a little early to begin guessing features for the PlayStation 5.