If I remember correctly, one of the lead designers was ousted (or resigned) from the days of iOS 7 and before.
From what I read (and which I know we can trust only so far), Forstall was ousted partially because he & Jony didn't get along, and Jony was rising in power. Jony, the guy whose idea of a Christmas tree for the warmest holiday and most-loving time of year is a lonely undecorated uncluttered tree in a wash of cold silver harshness.
LINK I don't know but certainly am curious to know whether or not Forstall worked on iOS7 or if he called it straight out for the pile of unnecessary changes it was, and then p.'d off Jony.
You have to understand, it's less about Apple copying than it is Apple following design trends. Look around, everyone has shifted toward large negative spaces, flatter designs, and less clutter.
Do you believe that Apple followed a trend? I feel Apple is, for better or for worse, the main trendsetter that everyone ELSE follows and not vice versa. Samsung phones physically morphed to look like iPhones, along with their software. Look back to the lawsuits of ~2008. Laptops started looking more like MacBooks.. As far as I recall, and I could be wrong, Windows and Windows phone's Metro Design appeared well before iOS7. I distinctly recall seeing the awful, flat, white/blue Windows Metro UI and thinking it was a mock-up or parody, but that it made sense for MicroSoft to come up with something different than Apple's iOS. Well how more perfectly different can you get other than to create the most bland, white, boring and unintuitive UI imaginable? I also recall the emergence of flat design, especially from Google, arising well before iOS 7, where to me it stuck out like a sore thumb as an example of lazy, uninspired, and overly simple boring doing design. Cue Steve Jobs dying, and Jony's penchant for minimalism and anti-clutter, and Jony's petulant disavowing himself of certain UI cues that "Someone Else was interested in, not me" (I so wish I could find an article I read where Jony scoffingly separated himself from certain admittedly rather cheesy woodgrain/felt design cues, saying something like "they weren't MY idea..."), and voila, the perfect recipe for a completely unnecessary flattening and decluttering of iOS, although with the baby and the bathwater, Jony & team also threw out many intuitive and pretty design cues that made an Apple product an Apple.
I hardly think the world was ready for something and Apple picked up on it... Rather, Jony was ready to have things his way and the world had to deal with it, followed by all the lemmings designers around the world following Apple's lead for better or worse, changing things to follow this imagined-needed decluttered & large negative spaced flat change for the sake of change.
By your argument, the world should soon be stirring for something completely new & different than flat, negative space, decluttered simpleness. iPhone OS/iOS lasted around 8 years from ~2005-2013, and 2021 is right around the corner. That is really scary to me, personally.
As for the overnight reinvention of every nook and cranny of iOS7... I left Microsoft for Apple in 2005 because Apple had a consistent design language that just hit it out of the park and they stayed with what worked. Smooth, basic, uncluttered, and super, super intuitive and super attractive. Just the right amount of extra detail and gingerbread to reflect a quality, polished and well thought out product. The games of radically reinventing their OS every 5 years was left to Microsoft, where each reinvention to me always was MSoft admitting they really blew it last time...so try THIS now instead! Then after 2013 Apple joined into that game with iOS, for the worse in my opinion.
As a designer, I can tell you most certainly these are design trends which have manifested across the UI spectrum. I recently booted up an old 2008 iMac running some ancient version of OSX, and the textures were more pronounced, the icons were more detailed, and none of it much looked like the modern design we have today.
It can be debated which design aesthetic is better, but these are largely interpretive choices that companies make. I used to be the Creative Director for a company called 321 Studios back in 2001-2003, and one of my responsibilities was the UI design in software (a terribly different time). When choices are made in software UI design, it's largely driven by the interpretation of consumer demand and what they expect to 'see'. There's a continual effort to simplify, strip away unnecessary detail, and focus deeply on minimizing the UI experience.
I've read words like that often and I still don't understand what's meant by "minimizing the UI experience." Not that I think iOS6 was the perfect do-all end-all that should never have iterated further, but looking beyond some cheesy wood grain, stitching, and podcast reel-to-reel player interfaces, what of any one aspect of the pre-iOS7 and pre-Yosemite OSX UI "got in the way?" I would contend that much of the new decluttered interface gets in the way much more than before. Much worse IMHO are the new stripped-down interface features with certain commands hidden out of site behind hamburger menus, and/or certain commands hiding behind a word with no actionable cues, a 50-shades-of-grey presentation where you can no longer tell the difference between content and commands (which often leads to frustration for me and many I know), or pages completely taken up by unnecessarily large images where you have to scroll with 10 finger swipes to see what's on one page (when you used to see it all on one screen at once, which was perfectly efficient...)
It was not uncommon for a Chief to drag an ignorant consumer into my office and demand that I work with them to meet their simple needs on our next version of software. This was not at all appealing to me, but it opened ideas into how average users of technology are attracted to software they otherwise feel intimidated by. It's not a one-size-fits-all solution, but it's a piece of the pie.
If you're still speaking of your early 00's experience, then I understand. But the world had a pretty darn good example of how a UI should be in the form of iOS & OSX until around 2013. So those times you recall where during the build-up when people were figuring things out. We've figured them out good, but then veered and lost the plot for the sake of fashion and forced change.
I do think iOS and Android look similar, but I too notice the differences. Perhaps the differences are less pronounced than they used to be, but they are still clear to me. As I mentioned before, my heart lies in the desktop experiences, and comparing, say Windows 10 to Mac OS is still vastly different in aesthetic and appeal. One could argue Microsoft has adapted ideas from Apple in this arena. Ultimately though, all companies should be deeply invested in simplifying the UI experience of their software and devices because consumers demand it, and design has shifted the playing field and the rules.
Consumers demand it, or a very small but loud population of pitchfork & torch bearers who gave Jony enough juice to create a bunch of change for the sake of change? I knew of not a single user desiring something new back in 2012. But I know an awful lot of frustrated users now (family & friends) when a certain iOS app is iOS7'd away from a previous great app...when it's morphed into an all-blue-all-white lots of wasted space on the screen with functions-hidden-away-behind-taps-and-hamburger-icons. Just to night (I swear to God) my mom was yelling at her iPad since her Acorn TV app was redone without her realizing it a few days ago...in place of their previous efficient layout where you could see many episodes of a season on the screen at one time, now you can only see one episode on the iPad screen at a time and you have to scroll, scroll, scroll to see the entire season. Before you could see it in one screen view. Before you could see a little marker indicating which episodes you watched. Now there's no more marker. Decluttered. And not for the better.
I contend much if not all of the current flat design decluttered iOS and OSX fad is for the benefit of the designers, not consumers. Just like architect students seem to love the blocky, brutalist, stretch-designs while regular people love just love centuries old architecture that has depth and took real design talent to create. If Apple really listened to consumers like some believe they do, this ridiculous all-glass design for the one object we carry around even more than the thoughts in our head would have received at least some type of durability/fragility improvement in the past 14 years, instead of mostly focusing on continually stripping way pixels and ports and the things that make something beautiful and fun and easy to use.
The main thing is, if a radical change occurred from within as I say, or as a result of outside influences as you say, then doesn’t make sense that we should be seeing a radical change again in a few years? Will that be good. I bet no — we’ll be back to Microsoft’s merry go round.