Copper Pipe from Backflow to ground

Today I was trying to clean up since I actually had a day off of work. I have been collecting used copper parts and pieces for 2 years now. I was looking through a crate of copper scrap and started to notice a pattern. After counting I found 37 copper pieces from systems where the foundation of the house had settled and broke at the copper/pvc connection. When you compare this to PVC you are 35x more likely to have a break with copper since it is so rigid. When the foundation settles and you have PVC going down to the ground the PVC will start to bow and tilt the backflow, when the tilting is noticeable it is time to add more PVC and straighten the backflow. With copper there is no sign that the foundation is settling. Some people get caught up in thinking the copper is the better way to go but I would have to disagree since I have seen more flooded basements with copper down legs then I have seen with PVC on the down leg of the backflow.