Why the iPhone 3G doesn't have voice control and a video recorder?

Question

Why the "old" iPhone 3G can't support video and voice control?
Is there a technical explanation?
Yes, I know that they're functions reserved at the iPhone 3GS
but why? Both have a microphone and a camera, the only difference that the 3GS has a faster processor.... so, does someone know why there is this difference?
Thank you very much for yours answers!
mat

Answer 1

"If the 3G offered all the same features as the 3GS, then there would be no reason to upgrade."
'If', maybe, but the fact is that the 3G is not capable ever of offering (due to hardware limitations) the same features as the 3GS, so surely such speculation is pointless and it is only wishful-thinking from those who are either:
1) not prepared to pay for the hardware that will support the facilities they wish were on their 3G, or
2) not prepared to wait for their contracts to allow them free phone upgrades to what will then be one generation beyond the 3GS, allowing the 3GS owners to complain about why their 3GS iPhones can't support the facilities of the next generation iPhones?!
My Mum told me "I 'want' cannot always 'have'....", so if I 'want' then I'll pay and if I can't pay then I'll not moan about not being able to 'have', just work harder or stay quiet until I CAN 'have'.
A wise old bird, my Mum!