In my 13 months with a barbell, one thing is becoming clear to me. Once you get past the basic principles for success (eat, lift, recover), and especially once you get past the beginner phase of fast adaptation, lifting is voodoo. A dark art. Sorcery.
Building on what csulli said, no amount of statistical knowledge will demystify the countless cause-and-effect relationships at play in a tiny subset of people who advance past the (relatively) predictable beginner phase.
Compound this very small population with the timescales involved, years to decades, and you have a phenomenon that does not lend itself well to having, say, graduate students study in-depth. Nor are results gained over the course of years and decades easy to reproduce. Have a new "theory" about the best way to total 2,000 as a natural powerlifter? Yeah... Start with an 18 year-old stick man and get back to me in 10 years with your test results.
So, when it comes to fitness and lifting in particular, I place a much higher value on anecdotes coming from the mouth of a big dumb lunk who has accomplished what I want to do than I would from the most heavily peer-reviewed study coming from weak geniuses who have not.
There is a lot of bullshit to wade through, and in the age of information we are perpetually knee-deep in it. Knowledge of statistics aside, I believe that having an intuitive feel for plucking good information out of the sea of bullshit is an increasingly valuable skill to have.