Also, we're not just talking iphone, ipod touch, and ipad anymore. There is talk of apple TV getting the OS. We have also heard rumors of the iMac getting a touch screen. The OS is rapidly changing, mutating, and being thrown on to a lot more devices. This OS could easily replace Mac OSX within the next 10 years Would a name like iphone OS really be the best option??
But the truth is the longer you wait, the more difficult it is to change a name (i.e. iTunes) so that's why the name change would have to be soon. My bet is that if we don't have a new name tomorrow, we will have one a year from now. Otherwise it's too "stuck".