I just read the release section of wikipedia and it doesn't sound like it took long for the iPhone to 'catch on'.
"As of Q4 2007, strong iPhone sales put Apple no. 2 in U.S. smartphone vendors, behind Research In Motion and ahead of all Windows Mobile vendors.[50]"
Im also pretty sure that, why its interesting, the benefit is still less than runing your outfit (literally) and this alone will be a deal breaker for A LOT of people.
Despite the price: A lot of corporate phones are top seller phones. I don't get budget from my company to buy this one AND any other deivce and you need both, a laptop and that device as you will not use it 8h a day