I disagree. Look at Toney Freeman. The guy is Levrone's age yet is just starting to place well... Toney took 6 years off training so in bodybuilding that would mean training+drugs, so I think that has a lot to do with how he's doing so well even at his age. Kevin's the same way in the fact that he wouldn't look old or worn out because of his time off drugs.
There's a reason "master's bodybuilding" exists. As a person ages beyond a certain point, maybe it's 40, maybe it's 45 (or 32 if you're Kamali), they simply are not capable of producing results as good as a younger person, even with all the drugs in the world.