Brodaiga,
I have had a slightly different experience. The iPhones are very popular here (I have one), and they are certainly less "disposable" than the previous cell phones offered in the past, as the replacement iPhone 3G/S models (and high-end Blackberries) from AT&T range from $600-$750 to replace a phone if it is damaged or lost.
Per GreggK, I feel from what I have heard anecdotally that many people (esp. due to the high replacement cost) choose to purchase insurance as part of their monthly contract for those phones.
I know my wife has used a repair shop to replace the keypad on her Blackberry after she spilled coffee on it, and they only charged her about $20 to fix it, which seemed pretty low to me. So those types of businesses do exist, but I'm not sure what the "viability" of starting one up from scratch would be, but if you are going to do it, I would recommend a very high-traffic area, maybe a kiosk in Plaza Las Americas or Carolina mall or something along those lines.
And Gary, where IS that rule written down that you have to be on the phone while you drive? I would say more like 80%!