This is inept design. If Apple wants to make devices so thin that they flex, they have to make them more rigid where necessary and allow for more flexing. There are true flexible PCBs, ones with parts on them, not just wiring harnesses.[1]
This isn't the first product where Apple has had this problem. It's embarrassing, or ought to be.
(I don't have this problem; I own a Cat phone (yes, Caterpillar Tractor) which can be run over by a truck [2][3] and still work.)