Always easier to just say "stop"
Fred Vogelstein does a dissection of the evolution of the iPhone in Wired. The takeaway for me is that there were nearly insurmountable hurdles in terms of investment, partnership, technology and even security, and that at any time, the easiest thing would have been to just say 'forget it.' Everyone would breathe a sigh of relief and move on. Important stuff is usually like that.
It was interesting to see that the code name for the iPhone was Purple2. I wonder if they were inspired by Alice Walker's book?