To relate this to Android, I can't think of any real reason S-Voice can't run on pretty much any Android phone. Once they saw it running on the competing HTC One X, they locked it down to the Galaxy S III immediately. You think S-Voice is rolling out to the Galaxy SII with their ICS update? How about the Note? The alternative is to see your work, like the Sony Bravia engine and (ugh) "Beats" audio hosted on some forum to download and sideload into a device that isn't netting you a dime.
I think Apple and everyone else for that matter is running out of ideas for Smartphone hardware features, so software is the new differentiation. Or at least, it is becoming a bigger purchasing decision maker than hardware.