Hopefully they do indeed hold off on 4K but I suspect that might not be the case this time. Rather it makes sense or not 4K is coming in phones from manufactures like Samsung and likely other laptops with 4k displays in the same size class. Apple may choose to upgrade as taking the hit in performance since they seem to be more focused on the general consumers of late in order to avoid getting an "Ultra HD Lite" label reputation with the Retina Display from that same group.
I can see them doing it with a Broadwell update by taking advantage of that extra gained 40% GPU performance boost putting it towards 4k. Would probably result in graphics performance being a little less then the current version befitting of the unfortunate trend that's also been going on of late(ex loss of the dGPU).
😀
Samsung hasn't put 4k into a phone yet. In fact the newly announced Galaxy S5 still has a 1080p display. The first manufacturer planning on going beyond 1080p is Oppo and they are releasing their phone with a
2k display this summer.
I think it is not even close to inevitable for 4k, considering apple has never been one to make such a strategic move as was going Ultra HD, and then riding the wave even further (from 3k to 4k, etc). They're going to stick with the current resolution for a while, until 4k is mainstream, I'm guessing. Which will be another 2 years or so.
I do however agree with the assessment that this years GPU (both Broadwell iGPU, and Maxwell dGPU) will help immensely with 4k if that is the intention (doubtful - in my mind).
In regard to IGZO (the original purpose of this thread, lol) I think we'll see it for the Broadwell update, and if not absolutely the following year. It depends on how mainstream it gets. Dell added IGZO to their computers this past fall, so I would assume apple takes advantage of it sooner rather than later; considering it's battery saving ability.
I wouldn't call it inevitable. Apple hasn't really brought back other products post cancellation. If they had planned to do so, they would have most likely continued the 17" as it was. Note how they did that with the 15" for some time. I think the 13" cmbp is still available.
They just axed the 13" cMBP a few weeks ago.
Edit: Just kidding it's still on their main site. But I read an article on here saying they did, so maybe it's was a date on when they would. Either way within 2014 it's out.