I think there are too many gadgets out now that is just overlaps each other's usages. My stepdad still has his first gen iPhone to play games while sitting in the john, but his main phone is the Droid X because he switched back Verizon after dealing with AT&T for only 6 months back in 2008. He also has a Samsung Galazy Tab where he usually checks his email because of the bigger screen. My mom has a cheap Pantech messaging phone, but also has an Amazon Kindle to read books. I may look into getting a BlackBerry PlayBook for my internet tablet since I may have to wait next year for a PS Vita. You even have the 3DS that can stream Netflix now.
So many of portable gadgets can do the same thing whether phones, tablets, portable media players, or video game handhelds. So it all depends on a person's situation and what they have. Now if I could choose to only have ONE device in my pocket and didn't have other devices, I would pick iPhone first. Only my 5-year old VAIO laptop is just as important to me because I prefer browsing the web on a bigger screen like most people who have an iPad or whatever tablet.
But I have options, so it doesn't bother me that much anymore if I didn't have an iPhone with me everyday. Owning multiple gadgets is like owning multiple cars. If one breaks down, you still have another to take you places.
Can I live without an iPhone? Yes, but this is based on my current situation and options I have.
Can I live without internet access? Maybe, but it becomes much harder than living without an iPhone. I need to check my email and be updated with the news.
Right now, my phones are lying right next to my PSP as I type this on my laptop. So it isn't a big deal like it used to be depending if you have options.