Huh?, I have read Mark's book cover to cover, and referred back to it many times. I don't remember anything about chains only lasting 1 or 2 k? Are you sure you didn't miss a zero? Or maybe Mark missed a zero? Or the printer/editor missed a zero? There are certainly such things as misprints. Also, I don't agree with everything written in Mark's book, and I don't agree with everything in the Clymer manual. FFS, the factory Honda manual is notoriously full of misleading translations and misprints and contradictions.
Years ago, I found this clever but silly app on the internet somewhere...you would put in your age and pertinent life choices and habits and it would spit out your life expectancy. Hmmm, smoker, alcoholic, little exercise except dangerous work place useing unhealthy materials, avid motorcyclist, poor diet, no family to speak of?...Well looky here I am 45 years old and I was supposed to be dead at 42. Now I am 53 and drink a bit less.