Apple to me has NOT lost it's luster. And this comes from someone who didn't even own an Apple product until nine months ago. Played a lot with them in high school/college (but those were Apple IIe).
I am ever the skeptic. NEVER buys a product on first look, NEVER ever bought an item from the old phone call solicitation schemes/methods. If I buy a product of ANY cost, it is researched repeatedly - and on the highest items of value (like vehicles) it's akin to a CIA/MI-6 sort of operation. Gather intelligence, investigate, do trials, be a painindeazz to forums the world over and to salespeople local. Work the "back and forth" of trial over time and getting info from others. Read. Read. Read.
Over time, things become evident as they apply to my use, and while I won't say "Apple is the best" as a blanket statement, I will say that for my use, both functionally as a device, and over time, Apple is clearly the best FOR ME. And it isn't even close when the totality is considered.
The three big things that make Apple the juggernaut on phones is that 1) superior software hardware integration, 2) general product quality, 3) software/security updates delivered uniformly and in a pretty responsive manner (yeah, I know, debatable in some instances, but if your text goes buggy in software and your mfgr/carrier has no fix, phone is done). Those three things make for "The Basics" that I consider important in a general sense. Particularly the updates being delivered uniformly and good for as long as Apple's updated software will run on your phone - the androids tend to quit updating after a couple of years, and with something as private as your phone, not updating it for security holes etc isn't an acceptable solution.
I am the guy who is the first to throw the "X brand is for fashion statement only" and other such barbs when I think the product is substandard. I live in a place that's almost entirely based on how the package looks regardless of whether or not it's hollow inside, and where "hollow inside" is often considered "elite". That said, I won't shame a product that becomes popular for being too shiny, or gains popularity from a certain segment. I don't care. Does it work? And since it's a phone, does it do it everyday, because it's my phone? Does it do it easily? I bought the Apple phone I own now (8 Plus, seemed like a phone I could live with) out of necessity/emergency, and bought one, just because I told myself for a while that I wanted to try them - and also knowing they have good resale. I took that phone on a holiday trip where that phone became HUGELY important (ticket trades blowing up and other meeting and business issues) and was sold on it within 48 hours. I had literally owned it for four days, and had to shoehorn two hours aside to get it set up before I left, but when I consider how easy that all was I know well why I pre-ordered for our second phone this week.
I'm not a "phone geek"/customizer - I seek to do what most productive people with a phone would want to do with it. I have no emotional side in the Android/iOS wars other than to find what works for me. It tends to bite in in the rear when I buy anything on that basis. My phone is much like my car - a UTILITY item and not a "fashion statement". It gets me to work and A>B. When I bought initial brand Car A and had service headaches with it on the basis of where it was made, rather than what the anecdotal and research reports stated, well I did it to myself. Afterwards I bought the brand I should have bought in the first place (it starts with T) and have never lost a vehicle to mechanical failure in 22 years of continuous ownership. There are cars with better ergonomics, better "road and track" drive quality (performance), and more "sexy" brands to be sure, but the reliability and being still pretty good in needed areas all around is enough for me.
Apple is a similar product. Performs well, quality build, has a good service record generally, and continues to hum along and change the game - even though it seems not in "leaps and bounds" anymore. But you're looking at devices, and not the bigger picture, which shows us that the device we know as a "PC" or Mac" is being migrated into your hand, more and more. It doesn't mean that cameras are obsolete, nor your desktop computer, or the Postal Service, or your bank teller/ATM, or your heart monitor. BUT - more of that moves into your hand - each and every day. THAT's the "news". It is Apple's job to move the public into that environment and make it as easy as possible to do it. That's where Apple RULES the market. Might the specific people find what's better for them elsewhere? Sure. But when Apple has that dominating of a presence against all other brands, they are doing something right for both ends - the techie/power user AND the more normal user.
For me, the latest example of Apple's gargantuan force in this year's announce wasn't the flagship at all. It's the Xr. That phone is going to CRUSH in popularity and be the hottest item under the tree. Why? Because it brings enough "new" to the table for the "normal user": Full screen, a larger format that's still sleek, choice of colors (that "product red" is HOT) and an all around phone that will be very good for most people and be a noticeable upgrade. People will buy a "third down the line phone" just because they will WANT IT. Sure the LCD isn't any better than an 8 Plus - but an 8 Plus still looks pretty good in the bigger picture. Apple will sell a bazillion of these, and while those of us wanting envelope pushing, next new earth shaking change, it's the "oh that guy, too bad it's......." that will be stomping in the market like an 800 lb. gorilla and making the beancounters party like no tomorrow. And it isn't a slouch, with A12 chip, and at $799 with a 128GB drive, it's Apple's way of bringing a baseball bat loaded with lead to the market.
Apple hasn't lost it's luster - at all. Their biggest challenge is that they have to be all things to more people. It's managing that which is their big challenge. If we had to earn a living by predicting what Apple will do next (and furthermore it's impact on the future of the company/what it says about the company) we would all be broke by now, and especially on internet forums where every day sans Steve Jobs had Apple one step away from that rhetorical downstairs place from which it would never emerge. History has proven different. If Apple goes down in any serious way anytime in two decades (I would guess) you will be worried about much, much more than Apple. You won't care about Apple in that instance. Which goes to show the degree of risk to "Apple" losing anything save for a few critics. Apple isn't going after just more phone sales, they're going after Google (own maps, probably own search, own music, own email wouldn't surprise - at least more of what Google does). It's wayyyyy beyond the specific device. But they are still pretty good at that device thing, too.