I'm very much of the opinion that apps were more effective as a viral marketing strategy than as a truly attractive feature. People talk about apps, people show their friends, but most of the non-geeks I know don't actually use anything but the built in apps, a Twitter or Facebook app and Angry Birds. A lot of people in the comments are generalising from their own experience and that of their peers, which is just a classic geek mistake.
I think Apple have been clever in perpetrating the myth that the App Store gives them an unassailable "ecosystem", but I think what really sold the iPhone was the fact that it's core features were so damned useable. Their rivals have been falling over each other to attract developers, when they should probably have been working on making the core features work better.
Look at the stats on mobile data usage - until the iPhone came along, nobody really bothered to use their smartphone's browser because the experience was so unpleasant. At one point 99% of all mobile data was being used by Mobile Safari. Android is catching up, but iPhone users still spend a disproportionate amount of time using their phone's browser. That has nothing to do with an "ecosystem".