So from that statement I assume that you have actually seen the comparison test results of GG vs the better other glass. If not then you are just pulling that statement out of some body orifice. The fact is that we don't know if there is anything better than GG, or even equal to it. There might be better glass or the rest might be inferior. Until I see a real controlled test I don't believe anything that anyone says, and that includes Corning or any other manufacturer. In addition, a controlled test is not "My girlfriend's GG got scratched but my other glass doesn't have any scratches."
There are also other aspects besides the actual glass. My Droid doesn't have any scratches after 2 years, but then it doesn't have a coating on the glass. If a phone has some diamond hard glass, but the phone manufacturer puts a soft anti glare coating on it, then the coating will scratch. The glass underneath will be perfect, so it is not a deficiency in the glass that is the reason for the scratches. I suspect that many phones now have some coating on the glass, so the only thing that GG does for that phone is add impact resistance.