A full discussion would take too long to type out. As you know the metallurgy of a KLR engine isn't exotic--it's pretty basic. That's not what makes the difference in oil sample tests.
Short answer: It's the operating conditions. E.g., whether the carb is running rich, the rider is hard on and off the throttle, city. traffic or highway, the air filter or oil filter lets more or less dirt through, the sealants used on covers and gaskets when replaced, whether it operates in a dry or humid environment, different fuel grades and additives, yada, yada. Sure, if you pull two engines off the assembly line and put them on dynos and run them for hundreds of hours in the same test profile on the same fuel and oil, the oil test results "should" be the same; but that's not what happens in the real world.
As BSL lab tests show, there's a wide range of wear metals and contaminants for the same type engines at the same mileage. Test labs have a large number of engines and oils and results in their databases, so if you paw through that data, you might find some trends with different oils in the same engines at similar mileage (unfortunately, I suspect that not many KLR owners do oil sample analysis, both because we are cheap bastards, and the analysis costs more than an oil change, so I doubt there is a large database for KLRs).
I read in one of BSL's newsletters a couple years ago about which oils they found were better based on their data; and if I recall correctly, they didn't conclude that there is a significant difference. I don't have time to go searching for that article right now, but it's out there somewhere

--which also supports my conjecture that the KLR isn't sensitive to the specific brand or type of oil.
Thus, comparing the samples from one KLR engine in one place and operating conditions under one owner to another using different oil and everything else, I don't think will yield a statistically valid observation, which is the reason for my "apples and oranges" analogy. Maybe I should say instead, that the noise overwhelms the signal you're looking for.
Thump on!