If anyone can convince the mass market that they care about a voice interface, it's Apple. But there are some things not even Apple can do, and I suspect this may be one of them.
Hasn't exactly that feature already somehow failed with the iPod Shuffle, which has physical buttons again? I haven't bought or ever seen that device or the 4th gen successor to make a hands-on judgment. But it seemed like a step back from VoiceOver from the outside. (I loved my 2nd gen Shuffle!)