The iPhone has other power hungry components (eg touch screen) that if the A717 had would kill the battery quickly. Having all these components in the same phone perhaps was not possible with the components available to the market at the time of the iPhones design. Including 3G may have required the removal of some other power hungry gadget they wanted to include. Or having all of these gadgets limits the iPhones battery size to one smaller than that in the A717.
But I'm speculating. In any event, those who wanted an iPhone and 3G will be able to get it and that is good news.
