As an engineer you design a product for it's intended use, with certain margins of error.
You do NOT design it to be ABUSED, unless you design combat equipment.
A phone of the size of the 6plus is supposed to be in the pockets of a sports jacket, briefcase, backpack, purse, portfolio, waist bag, etc.
It's not designed to be put in some tight jeans pocket of a super sized American behemoth squatting, sitting down or doing sit-ups. That's outside the design...