For a while now, it has seemed like a done deal that Apple's (NASDAQ:AAPL) upcoming OLED iPhone, commonly referred to as the iPhone 8 or the iPhone X, won't include Touch ID.

In a recent note from BlueFin Research Partners (via Barron's), analysts Steve Mullane and John Donovan seem to further corroborate that, saying that they currently don't believe that Touch ID will be included in the premium iPhone -- at least at launch.

Apple's iPad and iPhone running iOS 11.

Image source: Apple.

What's interesting, though, is that the analysts say that they are "playing with the theory that the parts and lasers will be designed in and added to future revisions."

Presumably, the analysts mean that Apple will add Touch ID to next-generation OLED iPhone models.

Here's why I don't think that'll be the case.

Once it's gone, it's likely gone for good

It makes very little sense for Apple to design Touch ID out of its premium iPhone this year, replace it with facial recognition coupled with eye scanning (as Bloomberg says Apple is aiming to do), tout it as better than Touch ID, only to bring the technology back with a future edition of the phone.

How would Apple go about selling customers on a feature that it had just made obsolete with its new facial recognition and eye scanning technology?

If Touch ID is truly out with the new premium OLED iPhone -- and I think the indications strongly point to this being the case -- then it'll likely be out with future iPhone models.

A potential way around this

Let's suppose though that Apple really wants to bring back Touch ID in a future OLED iPhone model because customers really aren't really buying into Face ID. And, of course, let's also suppose that Apple has managed to build an in-display fingerprint scanner that works well and can be manufactured at acceptable device-level yield rates.

How does Apple reintroduce the technology while at the same time not looking silly for hyping up Face ID (or whatever it's ultimately marketed as) as a Touch ID-killer?

Here's one way.

With this year's iPhone models, Apple can market the iPhone 7s and iPhone 7s Plus -- or however Apple decides to name these devices, which should be straightforward successors to the current iPhone 7 and iPhone 7 Plus -- as the mainstream iPhone models.

The premium OLED iPhone could be marketed as a device that's ultimately part of its own, separate lineup.

It'd be an inelegant way to do things, but next year's iPhone models could be marketed as the "true" successors to the iPhone 7s and 7s Plus (with this year's OLED iPhone being kind of an "experimental" product line), and as such the company could sneak Touch ID back in.

I only see this happening, though, if customer feedback around Face ID is poor. If the feature is well received and truly works better than Touch ID, then there's little point in investing the effort to bring back Touch ID.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.