Except for one other post everyone is overlooking one key factor...
Testosterone Levels!
We already know genetics plays a major part in how our bodies respond to resistance training with and without gear. We all know that even with tons of gear, training and nutrition the majority of us will never even be close to the pros. With that said let's look at testosterone. Our bodies only produce so much testosterone. Some men produce more than others hence their naturally bigger size and masculinity. Some men produce less and are small, typically weaker and sometimes even exhibit feminine type features. We know that testerone plays a huge part in promoting anabolism and reducing catabolism. We also know that through resistance training we can promote the release of additional endogenous testosterone that will allow the body to adapt to the new stress placed upon it. Unfortunetely, within our natural limits an interesting thing occurs as described below.
Before reaching our naturally determined maximum genetic weight:
1) We follow a resistance training program
2) We give our body plenty of rest to recuperate and eat sufficiently
3) We end up growing stronger and bigger as a result
As we approach our naturally determined maximum genetic weight:
1) We follow a resistance training program of increased volume and/or intensity
2) Out bodies require more and more rest to recover from the more strenuous workouts ( which reduces how often we can train )
3) Our bodies either cannot recover properly or are overly stressed due to the huge workload
4) Cortisol is going crazy due to the extreme stress place on the body, CNS, etc. and is surpassing the benefits of any additional testosterone released due to the resistance training
Bang! We reached our naturally determined maximum genetic weight. To go beyond this weight would require so much training or training at such a high instensity that even if you could get another pound or two on your body (I'm talking about lean pounds) it would require so much work between training, diet, supplements, rest, etc. that the return on investment would be terrible and not worth it.
So even if the use of AAS are beneficial in terms of stretching the muscle, etc. if the balance between anabolism and catabolism favors catabolism for whatever reason the body is going to catabolize muscle until my hormonal feedback systems says to no longer catabolize muscle. Can anyone maintain muscle mass while getting weekly cortisol shots? Of course not!
I strongly agree with all of those who feel the body will always go back to its naturally determined maximum genetic weight given enough time.