I agree that the iPhone isn't the end all and be all. I also agree that there are plenty of perfectly adequate phones on verizon and their selection of phones overall is better than AT&T's, but you could probably find phones on either carrier that would meet mot people's needs.
The iphone has a significant lead that the other manufacturers haven't been able to compete with yet and they haven't been able to effectively play catch up in the last two years. Their software is inadequate (including app stores), the hardware is better in some features, but the actual user experience of the phones is still generally behind the iPhone in significant ways (not counting, y'know, the network). And they're behind in marketing and branding.
They will catch up, though, and likely surpass, but it'll be a game of leapfrog when they do get there. Other manufacturers who may have longer feature lists and some nicer specs on paper will still lose (look at the mp3 player market over the last decade).