Thing about which I'm thinking today: There's a general assumption in the weightlifting community that even very serious hobbyists ought not follow the training plans of the drugged up genetic elite, being that they're neither of those things. (Assuming they are neither. Steroids change everything.) It goes further even than that, stating that much of what we know about training theory is severely skewed, having been too heavily influenced by a statistically insignificant pool of outliers.
(For a couple specific examples: The classic 6 day body part split and uber protein diets really require superhuman testosterone levels to work well. Mortals need less stimulation, more frequently, and can't make use of nearly 2 g/lb protein.)
For many fairly obvious reasons, this lesson could extend to endurance training. Don't think I've heard it echoed, however. In fact, I'd suggest we go the opposite route. Rather than disregard what they do, it seems we tend to look to the elites (athletes and coaches) for guidance and ideas.
If we assume that elite athletes have a decided genetic advantage (they do) and that many are getting chemical help (probably more true than we'd like to think), are we all idiots for more or less aping their training methods?
Yes, we basically always do less volume overall, and less volume of intensity. But the basic structure isn't that different. And it isn't really uncommon to see, say, a 2:40 marathoner training more or less like a 2:15 runner, despite being worlds apart.
Would the 2:40 guy be better off running 40 miles a week, with very specific hard workouts, and little overall volume? (The scientific literature would say yes.) Or maybe it should go the other way, with tons of easy miles. (The sub elite marathon times of the 1970's would suggest this.) Maybe he's got it perfect. Maybe it depends, and is wholly individual. Maybe everything works just about equally well, and none of this really matters.
I really have no idea.