You're right. Other companies are doing the same thing as Apple: prototyping, testing, iterating. Just not at the scale or speed that Apple does it. The media interest in Apple justifies the approach - with the curtains and the smoke and mirrors, other companies don't have to bother with all that. Apple has the scale, diligence and is being held up as the blueprint of how to do things the right way. There's no harm in it being a story about Apple, as long as historians realise that Apple didn't invent or make the only smartphones.
Perhaps for reasons of cost, the prototypes of the phones from non-Apple companies were "re-purposed" e.g. for destructive testing and therefore no longer exist.
edit: perhaps if other companies had the mindset Apple has (no limits, not even scale) then they would have to start introducing smoke and mirrors.
Another thing I see is that Apple, unlike the vast majority of competitors, have very limited product ranges.
This means that as a new iteration is developed, every Apple fan is focussed on that team's output. More so when the company decides to venture into a new area altogether (smartphones).
When Samsung produces a new flagship phone (let's say a new Galaxy smartphone), there's a good chance that a Samsung fan will actually have their eyes on another of the companies lines - the Ace, the Note, etc.
This very narrow product focus has helped them direct the attention of users and the media.
Ask any loyal Apple smartphone user worldwide which smartphone they're looking forward to most, it'll be the next iPhone. Ask the same of any loyal Samsung/Sony/LG user and there's a good chance it won't be the global flagship device they mention.
(FWIW, I say this as someone who isn't very fond of Apple or their products, but I appreciate their design and marketing prowess, in most cases)
Don't forget, the iMac G3 had five plastic color cases for some reason. Apple also sells a range of iPhone/iPad cases. Also, a major early selling point on the iPad was the magnates to better integrate with a case.
You hit on something, but didn't follow it through. Yes, other companies are doing the same business process that Apple is doing: Prototyping, testing, iterating. I would argue that other companies are also doing it at the scale that Apple does. Google's Street View and Book scanning projects have a huge scale
As you said, the difference is how Apple does it: out of the public eye. While all companies do internal dev and iterate a few times, it feel like Apple will keep something internal and iterate on something longer than others. The result is a product that feel more developed. It is often said that Microsoft needs 3 public releases to make some good (i.e. Windows 3.x was the first reasonable and "good" GUI). Apple hides those first 2 internally.
Go back and watch the iPhone launch video. Try and remember how crappy phones were in 2007. There are a lot of things the iPhone famously didn't have. However, the iPhone didn't feel like a 1.0 product. Clearly they had done a ton of work and iteration to make the features that did ship pretty well done and a great UX.
The first Samsung smart watches introduced last year were jokes with terrible compromises. Will they get better? Sure, But that happens in public.
Perhaps for reasons of cost, the prototypes of the phones from non-Apple companies were "re-purposed" e.g. for destructive testing and therefore no longer exist.
edit: perhaps if other companies had the mindset Apple has (no limits, not even scale) then they would have to start introducing smoke and mirrors.