Well, I've dropped dozens of different phones dozens of times, and the only one that broke the screen was an iPhone 6. Anecdotal, for sure, but it's what my experience is.
Suppose you got unlucky, most people do put them in some kind of shock absorbent case. The do extensive drop testing and a stress test Apple uses some of the best glass available, look at the reopening of the Iconic store in New York, Jobs was fascinated by glass, so whenever they improved it he replaced it. Originally the store was made of shorter pieces of glass and as soon as they improved it enough to replace t with one piece panels they did.