In terms of it being a design or manufacturing issue it probably is a small percentage. In terms of it being the result of folks bending the phone in their pockets, sitting on it etc, probably a higher percentage. But is the latter really Apple’s fault. I mean they have never claimed their devices are bend resistant much less bend proofThis is often the pre-requisite before Apple will launch a repair extension program.
Until then, Apple will forever claim a “small percentage” of owners are affected.
And yet Apple will bend the knee and repair the devices so they can avoid legal fees etc and folks will say that it’s proof of guilt when the issue could have been normal wear and tear (which is why it takes time to manifest) or caused by users