i don't know what you have done with your iPhones, but I've had all iPhones from a 3 to a 5S - not one of the above issues...
Same here.... I've owned all iPhones and never had any issues.
Same goes for a multitude of iPhone owners I know.
I suspect the resident PPRuNe Apple bashers are coming out from their caves to beat the drums on their boring bandwagon.....
As I said... if you sit on your iPhone, you drop your iPhone etc. then just like any piece of technology from any manufacturer, you can expect consequences.....and its most certainly not Apple's fault if you're a clumsy oaf or are ignorant of the basics of fundamental physics of putting a large load on an object that is not structurally intended for it.