Corning Gorilla Glass is hard, not tough (the two are a see-saw, the tougher it is, the less hard it is). The glass has a hardness of almost 7 (where carbide is 9 and diamond is 10), so it won't scratch, but that makes it more susceptible to breaking from pressure. (Try "breaking" Jell-O by bending it - but you can "scratch" it with a feather.) Until we have transparent steel, the manufacturers have to choose between hard (scratch-resistant) and tough (bend-resistant).
I go along with DSM - I always keep my phone in an Otterbox Defender. Even the holster is difficult to break. (I've dropped the phone a couple of times, once with a lot of force. After that, I won't buy a phone there's no Defender case for.)