A 2048x1536 9.7" panel would be such an abrupt jump, certainly for a relatively inexpensive mass market product. I think the best argument against it being plausible is that it has never happened. Again, Apple's not the only CE company in the history of the world with some money to throw around; if skipping a generation of anything were economically feasible but for some upfront money it would happen more often.
Or perhaps I'm wrong. Perhaps there's something genuinely unique in Apple's position as a cash rich company that controls its entire product and seeks competitive advantage through pushing key technologies. It may be that a ton of money up front is actually all you need to leap ahead, but no one was really positioned, till now, to make that a sound investment. Until the iPad there wasn't really any good reason to even want super high res 9.7" screen, unless it was for extremely expensive specialized applications. For all I know you can pay someone to fire up the foundry, work out the kinks, and go into full production at a price point that's sustainable for mass market. But then you'd still have to wonder at how you make a jillion of them, since Apple appears to have had a hard time just getting enough of their plain jane iPad 1 panels, and that's with several sources.
Yes, but what are we basing the idea that this is an "abrupt jump" on? As you say, nobody is using ultra-high-resolution 9.7" displays, but does that mean we can't make them? Do we really know when the iPhone 4's retina display became cost effective?
The article on Moore's Law and the retina display makes the following assumptions:
"We can assume that the biggest screens at "retina" density as of the iPhone 4's release - 960x640 in June 2010 - was the state of the art at the time. We can also assume that the iPad was the biggest you could go with the best process for that size at the time, 1024x768 in March 2010."
I think both of these assumptions are false. Firstly, June 2010 is, at best, an upper-bound on when the iPhone 4's retina display became cost effective. Surely it became cost effective many months before June 2010. Production would have ramped up long before then and Apple would have done its cost analysis earlier still. It's also possible that Apple could have used an even higher resolution display at the time but didn't because it wouldn't be exactly 2x resolution. Secondly, if Apple is planning to deliver a "retina display" for the iPad 2, it would have likely been aware of its plans when it chose to use a 1024x764 display in the current iPad. That display could have been explicitly chosen because Apple intended to use a 2048x1528 display in the second generation model. The iPad, I believe, was intentionally very conservative hardware-wise because it was an entirely new product category.
The figure he comes up with based on these two assumptions is 2012 for a 2x resolution update. If you believe the logic of the article but disagree with the assumptions, 2011 becomes a reasonable estimate.
I don't think even these revised assumptions are correct because I don't see any evidence at all that the computer and phone industry has been particularly interested in pursuing DPI. Android handset manufacturers, like PC vendors, choose displays based primarily on cost. Apple has been pursuing higher resolution displays and other manufacturers have responded by either offering higher resolution displays as an option or, eventually, moving to them as standard. But I've never thought of the PC industry, or the phone industry, as anything but extremely conservative on display resolution. So I don't think you can do this kind of analysis based on shipping products.
Personally I've yet to see any convincing evidence that a 9.7" 2x resolution display isn't cost effective right now. This kind of thing wouldn't be available to a start-up or small manufacturer, because they use off-the-shelf components, but to a cash-rich company that's heavily invested in the manufacturing plant and is looking to ship 20 million devices could do it if it's possible. And, like I say, I don't see any convincing evidence it's not possible. All that's been shown so far is that nobody else has done it yet.