Usually I would agree with you for features such as Siri where the noise isolating microphone was not present on the 3Gs or TouchID where the fingerprint reader was not present on the iPhone 5 however the features in discussion here have no need for new hardware to exist.
That's a bad comparison. Obviously the 5 isn't going to support it without a fingerprint sensor or secure element. We saw the Siri worked on old iPhones through jailbreak tweaks.