Guys like David Hsieh don't have a vested interest in any vendor. IHS Markit is vendor agnostic, they're reporting on the market and forecasting 2-3 years ahead.
For Face ID, there are obvious cost disadvantages. It takes up physical space and reduces space available for rear lenses, including future rear ToF sensor and VCSEL. From a usability factor, it's on par with Touch ID. There are issues with camera angle and it has issues with illumination in bright backgrounds.
Fingerprint offers continuous authentication. Every time you touch, you're authenticating. You can't do that without using large amounts of power with Face ID. Fingerprint is a thinner solution compared to Face ID/VCSEL. There are obvious cost advantages.
It's similar to 3D Touch story. It's nice to have, but by removing it, Apple gets a thinner package and a stronger display at a much lower cost. Apple can redirect materials cost to the rear lenses.
I wasn't saying the analysts have a vested interest in one company or another. Their job is to analyze and report on the prospects of the companies in an industry. If they see a particular company seems to have an advantage or disadvantage, I trust they'll be honest in their analysis.
Still, people's enthusiasm for a promising technology can turn out to be misplaced. Consider the (extreme) example of GT Advanced Technologies. That one took analysts, investors, and Apple down the rabbit hole. Claims for a promising new technology are only claims until the goods can be delivered.
There are always competing demands on space in a device. Perhaps it's necessary to eliminate one component in favor of another, perhaps not. Eliminating the depth sensor would save a bit of space, but the notch also holds the receiver (speaker), front camera, and proximity sensor - all of which would have to remain in one form or another.
Face ID may have been the justification for the notch, but it's not the sole reason the notch is there. They wanted to go to a corner-to-corner/no bezels display. Unless/until
all those items can be invisibly hidden behind the display, either a bezel or a notch is necessary, or your "edge-to-edge" display has small gaps or areas of poorer performance.
As to which is more power-hungry - validating ID each time a touch-screen is touched (which is near-constant, of course), or when it's being looked at (also near-constant)... The energy impact is not that easy to judge one way or the other. That devil is deeply embedded in the details. Apple claims the energy impact of Face ID is small. Would the addition of fingerprint ID to a display have zero impact on energy utilization? Maybe yes, maybe no. If tomorrow's fingerprint-scanning display used no more energy than today's non-scanning displays, I'd still ask whether other energy savings had been made in the display module to offset the energy consumed by scanning. If so, there's still an energy cost.
The 3D Touch story is a useful example. I'd argue that most users were not making effective use of 3D Touch, and for some, it was actually delivering unexpected/undesired results. It may be a feature that doesn't deliver on its potential and cost and if so, bye bye! I agree, any and all features/components should be subject to periodic analysis of that sort, including Face ID. The only thing that may separate us is whether we think Face ID would fail the test.
I happen to be a fan of Face ID, so I don't think it'd come up a loser. Its sensor array delivers a variety of features that go beyond ID verification, while a fingerprint scanner can do just that one thing. I'm looking forward to Face ID on Mac. The notion that my Mac can log in or wake from sleep at a glance is enticing (I enjoy Unlock with Apple Watch, but should Watch ownership be necessary?). A device that does not sleep so long as the display has my attention (no need to keep touching either display or keyboard) is a subtle but very nice convenience. Effectively, it's detecting my thoughts, rather than awaiting a separate, physical act. And finally, the notion that "air" gestures can be incorporated into the iOS and macOS UIs is also enticing...
At the moment, Apple is running an ad called "Nap"
highlighting the benefits of Face ID over Touch ID. I'm not going to use it as proof that Apple is permanently committed to Face ID. There are plenty of examples of Apple (and other companies) pushing its current "thing" right up to the second that they abandon/replace it. And while the overall story line is tongue-in-cheek, I will say that, as someone who uses an iPhone with Face ID as well as an iPad with Touch ID... Attention awareness/Face ID does reduce some of the "friction" of using my iPhone compared to the iPad. It really doesn't matter to me whether I have to touch a Home button or can touch any spot on the display - after having Face ID, reaching out to touch in any form seems unnecessary.
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