Could Apple put a sapphire glass screen in the next iPhone?

So Apple is using sapphire glass to cover the camera. Do you think it's possible to make the entire front screen out of sapphire glass? Apple sort of got rid of my number 1 complaint about the 4/4S: having glass on the back for no particular reason other than it makes it easier to break. If they replaced all of their other glass with Sapphire glass, we could finally use our phones without cases/screen protectors and without worrying about dropping/ shattering the phone.

I think it would be great to have as an optional upgrade, as it would substantially increase the price. It also follows along with the incremental upgrade policy that a 5S might entail. Regardless, this upgrade should be something that Tag Heuer or other luxury modders might consider.