My point is just that the shape of the iMac isn't exclusive to Apple anymore. I think looking the new iMac face-on the average consumer wouldn't know it was Apple.
The shape of the iMac might no longer be exclusive, but that doesn't mean Apple have a reason to move away from it.
This overall styling has been part of Apple's language since the original Mac in 1984. That HP and others have sought to copy it demonstrates how effective it is as a 'style', and perhaps for practical use reasons too. It suggests that Apple are designing it right to be at all widely copied.