My chain of events was this: Blackberry to non-smartphone to iPhone then to Android.
As you said, Blackberry was mainly a business type phone and while BBM was awesome, it was only really awesome when you were chatting with other BBM users. Once I found my way to the iPhone, I was hooked. But in short time, I realized I was mainly hooked by the ecosystem that having a smartphone today requires. With iPhone and all other i-devices, you're very integrated with iTunes, iCloud and the App Store. While these are not horrible services, I just found that I was using Google more; mainly because I was a Google user way before the first iPhone came out.
As Google became more entrenched in the Android project, they started offering services that rivaled Apple. So for me, my reason for switching was just because I saw more value in Google's services as they pertained to my usage. In other words, I was already using Gmail, Google Apps, YouTube, AdSense, AdWords, Analytics, Google Voice, Feedburner and the list goes on and on. Once Google changed their app store to Google Play and started adding all the media content (music, movies, tv shows, etc.) it really was a no-brainer for me. To top all that off, I use Google as my main search engine as well as for my social networking profile on Google+ as I slowly phase Facebook out of my life!
Wow, after going over all that I really am a true Google user!! Interestingly, I haven't said anything about devices yet. But then again, that's the point I was leading up to. Today, the choice between iOS or Android isn't so much about devices and specs anymore. I think you're going to find users that have become entrenched in their own preferred ecosystems and they will sort of be stuck with whatever devices those ecosystems provide. The phone wars are dying down now that major playing fields have been established. And just like there are major Google users using Android and major Apple users using iOS there are plenty of Microsoft users using Windows.
Of course there are tons of people that aren't as connected as say I am and it's these people that will still buy phones just because it has a certain feature or because they get tired of one operating system, but for the rest of us, the manufacturers are going to have an increasingly harder time to make us switch.
I am currently a user of the Nexus 4 as my phone and the Nexus 7 as my tablet. I went a step further and decided to use pure Android devices since I got sick of Samsung's TouchWiz version on my Galaxy SII. In just one week, I'll be the proud owner of the Google Play Edition of the HTC One which is yet another stock Android device!