Yes, but reality how many people have flint-gravel drives and how many of them regularly drop an unprotected phone onto them?
I'm reminded of talking to a friend many years ago when I bought a ruggedised torch to replace one that had broken when I dropped it while up a step-ladder.
"Ah", he said, "but it wouldn't survive a 100 foot drop onto concrete, that's how most of my torches die.". (He worked for the National Grid at the time.)
Do you know what? He was probably right, it wouldn't have survived that. But then I wasn't planning on putting into that situation and never did. All I needed it to do was to survive a drop of around 6-7 feet onto carpet or possibly lino, and it did that.
Eventually it died the usual torch death of being left in the back of the drawer and then eaten from the inside by its own leaking batteries.
Point is, if you have a flint-gravel drive that you regularly drop your phone on to then an all-glass phone is probably something you need to avoid, or maybe buy a case for it.