I to am on the Gorilla Glass bandwagon as well, and a big big fan of Corning. But Gorilla Glass is under patent. Synthetic Sapphire has been around since 1902, and it was cheap back then. Sapphire is hard... 9 on the Mohs scale, and the only substance harder is natural and synthetic diamond. I find it difficult to believe... so...do you have any references that says Gorilla Glass is cheaper and harder than Sapphire?
I'm not the parent poster, but here's a ref claiming that Gorilla Glass is indeed both cheaper and far weaker than sapphire.