It's not about how you might use the device. it's about how people actually use them. Maybe a dozen ppl have ever used the browser on a PlayStation. When you lose your phone, on the other hand, it literally feels weird to go about your day without one.
Right now you have a "Hobson's choice", but if you could ditch the iPhone while still keeping access to iMessage and iCloud, wouldn't you?
I don't really care about iMessage or iCloud. Yes the blue text looks nicer and the quality of images in messages is a little better, but it's not a deal breaker if I'm messaging an Android user. I have less than a gigabyte of stuff in iCloud and I don't know how it got there.
I use iPhones because they're smaller than Android phones. Would I like it if Apple still made phones in the form factor of the iPhone 4 or 5? Absolutely. Should the government force Apple to do that? Probably not.
Right now you have a "Hobson's choice", but if you could ditch the iPhone while still keeping access to iMessage and iCloud, wouldn't you?