I have the same longevity experience with Shimano's chains. Granted that I'm a spinner, but I'm spinning 5,000+ miles a year up and down mountains and I weigh in at 170-175 pounds. With only average maintenance and proper installation, I seem to get a LOT more life out of my bike chains than the average BFer. I don't think I have ever replaced a chain due to the chain wearing out (i.e., "stretching"). I understand how a person could ruin a chain by leaving it out in the rain, but how do you wear out a chain in 2,000-3,000 miles? Bicycles are very low-stress applications for chain.

I tend to think that the removal/installation process is more likely to ruin a chain in less than 3,000 miles than the chain is to wear out in that time.