How do you know that the case saved the day? I once had my case-less iPad fall from a ledge five feet above the surface it eventually landed on and it survived with nary a scratch. They seem fairly rugged on their own.
More than once my rubber case has stopped my phone from slipping off a table. I won't get into the details, but the toilet incident of 2011 was a close call and the case prevented certain disaster.
I remember when I first got smartphones around 2006 or 2007, I was breaking mine every 6 months or so. I currently have the original galaxy from samsung, and it is still going strong over 2 years later.
I think the cases were really important, but once the HTC Hero and that generation came out, then magically my phone lasted years!
Mine fell from a table about 80cm high, screen flat down on a hard floor. Got just a ding on the corner (and a heart attack). I've dropped an iPhone 4 probably a dozen times too, it's an year old, caseless and healthy (though you can see some light scratches if you look close enough).
