It's nice to have some confirmation of what I've been saying for a while. Face ID is not "Plan B" technology. The narrative that it was rushed to market when under-screen Touch ID didn't pan out doesn't jibe with the realities of R&D and product development. In that world, you start several parallel projects and choose the winner. Since the tech behind Face ID is far more sophisticated, research would have been started well before under-screen Touch ID. The only question a year ago, when decisions of this sort
had to have been made, was, "Is it ready for prime time, or do we continue with Touch ID for another year or so?"
Engineering types would simply salivate over the possibilities afforded by the various components needed for Face ID - components that enable far more than simple biometric ID. That array of 3D components would make the launch of ARKit that much more powerful. They'd have been pushing for Face ID from the beginning, and lobbying for Face ID would likely have been far more passionate than for Touch ID.
Why go through the effort of having a haptic feedback, solid state Touch ID in 7/7+ and continue it with 8/8+?
I think apple knows not everyone will adopt to Face ID only trend, so they offered the alternative too
The fewer mechanical buttons there are on the iPhone, the easier it is to achieve the desired level of water resistance, and the lower the cost of warranty support (broken buttons). I'm sure eliminating that mechanical Home button was a long-desired goal in engineering - it gets by far the most duty-cycles of any switch on the device, so solid-state was the way to go.
I can't predict whether Touch ID will be phased out in new models after another year, or maybe two, but since the 8 will be produced and sold as a budget-friendly model until at least 2019 or 2020, Apple isn't losing the money spent on developing that particular bit of tech.
Haptics weren't developed for the Home button, they were a useful solution from Apple's existing bag of tricks. They're put to far better use in TouchPad and Watch. So again, if Apple uses it in new model iPhones for only a few years, no loss.
I doubt Touch ID in the 8 is an example of hedging bets. Apple, the company that put "creative destruction" on the map?? It's purely a matter of money and time. That bundle of Face ID components is much more expensive than a solid state Home button. If you want to keep the price of the 8 within range of the 7, then Face ID is out of the question, for now. However, the next generation of Face ID components will be cheaper, and probably more compact. At that time, they'll be ready for the mainstream product line. As with automotive tech, new technologies need early adopters with deep pockets - the gee whiz stuff at GM usually starts out in Cadillac, not Chevrolet.
Mainstream skepticism about Face ID can only be overcome through time and positive word of mouth. For now, it's not trusted - but it will likely earn that trust over the next year, as Touch ID did.
