Bear with me. This one's simple.
A growing body of research indicates that fracking an oil well has less effect on total output and more effect on how fast that output is achieved.
In other words, without fracking, a particular well may have had an estimated X thousand barrels of reserves and an estimated Y barrels a day of output. With fracking, X may go up just by 10 percent, but Y goes up by 30 percent.
Result? An apparent gusher that runs dry pretty quickly. (Or, runs dry enough to call for the attempt of a second, even more brutal frack job.)
Light bulb going on in your head now?
Allegedly roiding players had a much greater per-season output, but then, either chronic or acute use-related injuries hit, and the total output wasn't that much greater.
For a player who had greater pre-roiding estimated reserves, a player like a Barry Bonds or Roger Clemens who were at Hall of Fame level without roiding, the decline wasn't so severe and the plateau was higher.
For a Ken Caminiti? Different story.
Food for thought.
And, explains why some players just don't benefit as much in general. You have to have something to build on. You have to do weights and other work to bring out what you're doing with the using. And, even then, things like metabolism may still have an effect, just like some geology works better for fracking than other.