Why do iPhones screens crack so easily? I had $20 phone that I threw into a wall and it left a dent in the drywall but the screen was fine. Recently, I just dropped my LG on the concrete without a cover and the glass is completely unscratched.
iPhones use glass from Corning, just like a lot of other manufacturers, but it's not Gorilla glass, it's ceramic coated. It actually performs pretty similarly to Gorilla Glass Victus, but allegedly has slightly better scratch resistance. With that said however, modern glass like Victus and Ceramic does make a compromise over surviving drops over scratches. You may could have got away with not putting a protector over say a phone with Gorilla Glass 5, but you really should put one over one with Victus because it's more likely to develop microscratches, which over time does compromise it's drop resistance.
And if you are talking about the back of the iphone, at least with the 12, the back wasn't ceramic glass, the back is Gorilla Glass 6.