Even if it was friction, it should last a lot longer than 5 months. I've never had a cable go so quick as this before. If the friction tears at the cable strands so badly that it snaps so soon it must be a design flaw.
Yeah, probably the machine that attaches that end onto the cable strands, but my bike is brand new and I checked mine and it is bone dry where that thing locks into the lever. I packed some moly grease in there with a toothpick and lubed the end of the cable and it does pull a bit easier. When the dri-slide I ordered shows up I will lube the rest of the cable as well. I have never had cables that I didn't lubricate on any bike.