Well, most of us were born with normal fingers, without the suction cups you seem to have.
As an imperfect human, with some clumsy tendencies and having borne children, I put protection on my phone. I do not have the time, energy or stamina to hold it in a gorilla grip at every minute nor set it in its plush cradle when I’m not using it.
I manage a university IT help desk, so I see a lot of smartphones. My casual observation is that many people drop their phones, because I see a lot of cracked screens (iPhones, Android, and a few Windows phones). Seems like a lot of people live with the cracks, especially students. Students often buy used phones and would rather save up for a better used phone than repair the one they have (depending on its age). There is a mobile device repair shop about a half mile from campus that does brisk business.
I like to think I'm more careful/less clumsy than most, but I have certainly dropped my iPhone. When you pull something out of your pocket so many times a day, odds are an accident will happen sooner or later (especially if you have kids). These things ought to be designed to withstand drops more than they are, but I guess that's why they sell Applecare and cases. I still think putting glass on the back is a troll move