This is mostly a good point, but is missing an important difference. A lot of important Android APIs are provided as part of Google Play services and made available back to Android 2.3, whereas an iPhone 4 running iOS 7 still will be unable to use Siri.
I understand your point, and it’s a good one, but iPhone 4 isn’t allowed to run Siri because of hardware reasons, not API support. The noise reduction in newer models is a lot better than on iPhone 4. Hackers have managed to get Siri running on iPhone 4, it just doesn’t work as well.
