When these reports like you posted started coming out I started lubing the cables inside the cable holder in the shifters periodically with Tri-flow, the one with the long needle dispenser and know I get much more that the life than your post (sorry I have too many to keep accurate records) but as you no doubt know that greatly depends on the shifter, housing, cable quality and environmental factors, etc,. The only problem I have encountered is when a few strains broke loose from the cable in a Shimano shifter long after initial break in period and I looked and found the cause of the stretch. I agree the reason you could not get to the small cog, a big clue, was a few strands broken loose hanging up the cable not allowing a full return to slack cable.