You need to understand that you're comparing apples and kumquats.
Heh. I said "apples".
Anyway, consider this: the iPhone is fully integrated. The hardware and software are designed - and integrated - by the same company, by cooperating and coordinated teams. The integration is fluid and seamless, and regularly updated on both hardware and software fronts in a fairly predictable manner.
The core OS is based on the same core as the Mac series of products. It's very, very well developed, having been running in constant production more-or-less since Steve Jobs' days at NeXT, like about 1989.
The user interface is based on Cocoa, which has been around just about as long. It's one of the oldest continuously operating model-view-controller user interfaces in the world.
That doesn't mean that it's not without flaws, but all the flaws are captured under one tent.
Consider Android phones. Android phone hardware is developed independent of the operating system and user interface software. Some tout this "openness" as a good thing, but before you get on the fanboy bandwagon, consider what it really means: it's trivial to introduce bugs at the core OS level, because so many things wind up being device specific, and all the specific devices are different.
Plus, now that the OS has been commodified, how does say Samsung differentiate their Android phones from phones by say HTC? Unlike iPhones, where your user experience is effectively identical REGARDLESS OF THE PHONE YOU HAVE IN YOUR HAND, the user experience for Android phones varies radically. Sure, all the basics are the same - mostly, except where they were changed just to add "differentiation". But the rest of the UI? Not so much.
Add to that the "special sauce" that US based carriers insist on adding, and you wind up with the same phone, running the same OS release, having different features. And no one - literally, no one - has a consolidated view of all of the moving parts in the system. It's like Windows on PCs. It's EXACTLY like Windows on PCs - the OS tries to run on everything, and while superficially it does, all the fiddly bits are different enough that stuff just breaks.
As an app developer, it's a nightmare. You have different Android releases, possibly running on the same phone, that behave differently than the same releases running on other phones, and from each other. That means your testing universe has to potentially cover every phone on the market. Literally, every phone.
And then you have the difference in the app distribution systems. At Apple, it's a pretty painful process - your app undergoes intense scrutiny. Did you follow all the requirements? Are you trying to "get away" with anything? Does it crash? Is it derivative of something else, in an infringing way? Is the UI consistent with the expected UI for apps running on iOS? The list goes on. But the end result is rewarding: apps in the App Store work, as expected, all supported devices.
Contrast with Google Play, where the process is much more "streamlined" - meaning no real scrutiny. And where you find copies of popular apps with the titles slightly misspelled or altered, delivering malware payload in addition to being actual decompiled and recompiled versions of someone else's work.
I could go on, but I think that's sufficient. I'm an OS guy, an embedded systems guy. I love doing that sort of work. I've tinkered with the Android OS, done my own builds, tackled some of the outstanding bugs (haven't submitted commits back as of yet). It's... interesting. Not interesting enough to spend more time on, but interesting. I can see where they were going in the design and architecture.
But what the wound up creating is a platform that by its nature commodifies phones that use it, and creates chaos for developers.
Me? I'm rocking an iPhone 6+, which is my fourth or fifth iPhone. Because I like my phones to work, not be science projects.