Good post.
I do think the limit of muscle mass haven’t changed. The only thing which has changed is the level of conditioning these days. Even natural bodybuilders are demanded a striated glutes and most do have those.
I think the problem with such greater demand for conditioning is that natural bodybuilders look a lot smaller. I think they should relax a bit on the conditioning part.
Talk about training, I don’t if there will be a difference if the current natural bodybuilders train 3 times/week full body workout like Reg Park or Steve Reeves. But then again these guys are probably would have grown on any messed up routine.
Have you looked at Jim Cordova. He is another genetic freak who has a pleasing physique.