Okay, pop quiz: what’s going to be on the next iPad’s feature list?

You’d probably say one thing right away: the same Retina Display that has made the iPhone 4 such a treat. After all, one look at the precision and crispness of that display, its indistinguishability from paper, its placement directly beneath the glass such that you feel like you’re manipulating the pixels directly, and it’s clear this technology will be propagating everywhere Apple needs to show stuff.

Some developers I follow on Twitter talk about the Retina Display like it’s a sine qua non; without it, the iPad (which lacks it) is a greatly diminished experience. Apple must love to hear that.

This hasn’t been my opinion. Since acquiring the iPhone 4 last Friday, I’ve marvelled at the quality of the display, but I noted that it hasn’t changed the rules for how and to what extent you present information to the user. In other words, while the pixels have gotten smaller, your finger is stubbornly the same size.

But that’s not to say I won’t be excited by the Retina Display-enabled iPad when it arrives. And that’s the nut here: Apple is the expert at this technique of predictive marketing, and they’ve been doing it for a very long time.

For a company that has a track record for introducing “totally new” products (the iPod, the iPhone, the iPad), there’s always a thread, a technology story, that users can trace from what already exists to the new device. The Retina Display is just the latest example. Go back one step: before the iPhone 4 came out, we had the iPad with its super-fast Apple A4 chip. The company went to great pain to tell us all about it. And the early press, along with direct experience, showed us that the A4 was indeed blindingly fast.

Gee, wouldn’t it be great if that chip were in the next iPhone? So when that did happen, we already knew what we were getting, so to speak. No matter what else the iPhone 4 featured, we knew it would run apps like nobody’s business.

Other examples abound, where the company has introduced features on one platform, and rolled it out to successive generations of product. On the Mac side, recall Apple’s introduction of (what I like to think of as) their next-generation power management system, on the 17-inch MacBook Pro. For the first time, they offered a ten-hour battery life, owing to a significantly larger battery and vastly improved electronics for managing it. I had just bought the previous-generation 15-inch MacBook Pro, so I was stuck with my measly 2.5-hour battery life.

Over the past two years, that technology has trickled down into all of Apple’s laptops, even the white polycarbonate MacBook. And I couldn’t be more excited: I know what I’m getting when I get my next laptop, and that improved, well-understood benefit will ensure that I upgrade.

The ignorant people talk about Apple as if they’re all about surface appeal. We know better: many companies — including Apple — nail that on the first iteration of a product. But the company continually hones its offerings, adding new improvements that are so clearly superior to what they had before, that users feel compelled to upgrade. Hence the lines on iOS device launch days.

No other company is in a position to so successfully work their customers in the same way. I dismiss Microsoft and its PC hegemony out of hand — they are more interested in preserving their lead and stopped innovating years ago. Google with Android comes close, but its hardware ecosystem is so complicated that we need a scorecard to tell the difference between identical hardware from the same vendor (Samsung, I’m looking at you).

How the hell are users supposed to connect one innovation with the next-generation’s offering? In short, they can’t. And that means a customer isn’t going to have a particular loyalty to the brand. That customer will buy whatever phone the guy at the store recommends that year, and they’ll probably come in again two years later and do the same thing.

An Apple customer, on the other hand, will actively seek out the next iPhone when their contract is up, and they’ll know exactly what they’re getting: something already great, but even better. Apple has spoiled us for the next model, and every launch is not just an ad for that product, but for the next iteration of the other products.

Ever get the feeling that this company is an unstoppable juggernaut?