Although the hbar bag is forcing the cable and housing to follow a sharper curve, it is unlikely the cause or contributor to the failure of the cable. It is an age old problem that has no relief with the current design of brifters and the shifter shown in the original post. Simply put, do as others have said, change the cable before it breaks, and if that means annual replacement, so be it.
The rear der cable on my brifters lasts about 4 seasons, the front I have yet to replace as it does not get used nearly as much as the rear.