I suggest the book "The Sports Gene", the author is Epstein or something like that. It's all about this kind of stuff.
The short of it is you can put different people on the exact same exercise program and get vastly different results.
I haven't read the book so I don't know what it asserts.
But, someone could be doing the most efficient program without getting much in the way of results, simply because he doesn't have many muscle fibers, has short muscle bellies and due to a host of other genetic features. Still, the stimulus for growth is the same. Just like no sprinter will get better by only running marathons no bodybuilder will grow best by doing 50 sets of 100 reps every day for each muscle. It's like with drugs, some metabolise drugs faster and may need a little higher dosage compared to someone else for the same effect, but people still respond pretty much the same with some minor variations.
If everyone needed some unique program to progress at all you could forget about programming in any sport, it would be an impossible task to train anyone successfully.
Very interesting. Layne Norton pulled 677, and failed at 700. Ronnie Coleman in his powerlifting prime pulled 747.5, and failed at 752 while having about 40 lbs more bodyweight than Layne. Essentially, Layne is pound for pound much stronger than Ronnie Coleman was in his prime. Amazing what hard work and determination can do.
Don't forget that powerlifting is a lot about angles and leverages and technique. Like turning your feet out an inch and adding 20lbs to a lift, that sort of thing.
And genetic skeletal structure. Look at this pic and you immediately see why this guy has an advantage in deadlifting. That's why judging demonstratable strength and connecting it to drugs is tricky.