Why is Siri iPhone 4S only? [closed]

Seems odd to me that the Siri assistant feature would be available only for the iPhone 4S. I have the Siri app (from the company Apple bought and integrated into the OS) running on my 3GS and it works just fine. So what gives? It surely isn't hardware. Then what? Just to move more 4S units?

Solution 1:

It's supposed to use the phone's processor to do the voice recognition instead of sending the recording to the cloud to recognize as the Siri app does. This (apparently) requires the A5 processor.

It probably doesn't hurt, though, that it'll push 4S units.

Solution 2:

The other theory I've heard is that voice recognition and text-to-speech takes up a lot of RAM, and coupled with the suggestion from a couple of tech writers who got some hands on time{1} that the 4S actually has 1GB of RAM, it makes some sense.

It would also explain why the iPad 2 doesn't seem to be getting the Siri stuff, despite having the A5.

And having it as a feature to push upgrades sure doesn't hurt either.

{1} John Gruber from Daring Fireball on the 5by5 coverage of the event and Josh Topolsky from This is My Next