I think it's a combination of a bunch of things some of which was mentioned above but I'll recap anyway:
1) Non-Intuitive Set Up: I imagine most users look at things like 192.168.1.1 and wap.voicestream.com with a deer in headlights stare. It must be said that recently iMate at least has been packaging operator settings making this much easier.
2) Uninformative/Non-Existent Error Messages: The things just fail generally. Any error message you get doesn't mean a thing.
3) First Tier Support: In a word - useless. I have never, ever gotten an intelligent response from first tier support for a set up issue. Sadly, I don't often do much better the higher I go. I would hazard a guess that most people don't have the inclination (or the frustration tolerance) to crawl their way up the food chain which can take days.
4) 'Optional' Functionality: Get an iPod that doesn't play music - you'll spend time trying to fix it. If your phone won't make calls - you'll spend time trying to fix it. Sending a picture of a puppy - if it's important to you you'll spend time trying to fix it, otherwise, the phone still makes calls...
5) Not Enough Obsessive Geeks: Much of my life is W?BIC. For instance, I have never sent an MMS message other than to make sure it works & doubt I ever will. That said; I will stay up til 4 AM, tear apart the internet, and suffer through what passes for customer service these days to make sure it does work. No idea why, just the way I am and I suspect I'm not alone on this. My mood is actually impacted by my success or failure. I'm guessing most people probably spend their time with their families, helping the poor, or some other meaningful endeavour - they really need to work on their priorities...
#5 got me thinking and I've done a poll on it here:
http://www.pocketpcthoughts.com/foru...=374106#374106