One theory is that the failure is the rubbing of the ribbon cable on the inside of the case. Even though the inside of the case feels smooth it is not and the cable rubbing wears through the thin cable cause a ground to the case. You can't actually see this rubbed area. Another theory is that where the cable is forced to make a right turn where it goes around the DVD drive, that one of the conductors break in that area.
I have replace three of these, each of my 2 2012 MBP 13 inch and on a friends. I used clear packing tape where the cable runs underneath the hard drive / SSD so it does not rub on the aluminum. One has been that way for six years, no problems yet.
As an aside, put an SSD in it, you love the speed increase. But, be aware that the computer may work just fine with the hard drive but when you put an SSD in it you could have problems. I have read that because a lot more data is moving when using an SSD a failing cable can't handle it.