That's one advantage to Android. You can change manufacturers for your phone and retain your investment in the eco-system without much issue.
I would say the other side of that is even more important—and a huge advantage for choosing iOS:
Changing from one Android phone to another, last I checked, was a major hassle, even with the same manufacturer, and even if none if your apps ended up incompatible (fragmentation).
Why? Because as near as I can tell, Google STILL has not fixed the glaring problem that when you switch from one Android device to another, you lose all your customizations, game progress, stored files/music/movies, screen organization, downloaded apps, etc. It’s like starting fresh! What a pain. That’s not the way for your market to be “sticky,” when an iPhone user can get a new iPhone and everything from wallpaper to folder organization is preserved—automatically with no special hoops to jump through. A clone of your old phone, with the new capabilities, thanks to the complete backup that iTunes provides.
So in reality, Android is an “ecosystem” where you LOSE much of your investment in it every time you need a new phone, even if the reason is that the old one didn’t work! Whereas iOS preserves everything for you painlessly.
My iPhone is the home of WAY too much of my life to put up with having to start over like that. And to make things worse: you face the same problem if your Android phone needs a warranty swap! Has this been fixed yet? Can you (finally) get your Android phone swapped and have 100% of your old phone cloned to the new one as it should be? Or is it still a halfway “some things will synch and then you’re on your own”?
Meanwhile, what benefit do most people really get from changing from one Android manufacturer to another? Some benefit, yes—but not as much benefit (for nearly all users, if they realize “open” is pure marketing) as just switching to iPhone and iOS's far-more-complete ecosystem. With a retina display, unmatched integrated music store, no malware, and no worries about the wrong app killing your battery life so you can’t make a call when you need to. (Seriously, my Android friends get less than half their calls and emails on a timely basis, and they lug a charger everywhere—how do they stand it?)