Just some correction on Charles Poliquin, who was a friend of mine.
First, the second picture was when he was in his 50s and riddled with injuries that prevented him from training hard (if at all).
I will say that he had poor genetic structure to "look like a bodybuilder" in that he had very narrow shoulders (bone structure) and very long limbs for his height.
BUT he did have a strong response to gear.
I remember we were having lunch together in Colorado a few years back (probably 10 ish)
He wore a sleeveless shirt and looked like an "old man who used to train". Although he was not "old" at that time (mid 40s). But you know the look: you could see that he used to train hard but the muscles were like deflated remnants of what they used to be.
4 weeks later we were giving a seminar together and when he showed up he looked fucking JACKED! Especially the arms. Very big, shapely and separated (so much better than the first pic you posted). While the arms were impressive, the speed at which he went from the old deflated look, to hard like stone was shocking.
The thing is that Charles actually lost his passion for training once he became more of a businessman. Once he switched to having his own supplement company and giving seminar rather than coaching it's like he stopped caring about training.
He would actually train intermittently. In spurts of 6-8 weeks in which he would train fairly hard then barely train for a few months.
And as I mentioned, at one point he was plagued with some many injuries (especially shoulders) that he just couldn't train hard at all.
As for steroid use. He had a genetic heart problem. Few people know this but he actually had very frequent "mini heart attacks". So he didn't stay on steroids for long (it would actually have been a lot smarter not to use anything at all, especially considering how he died). It was really be on steroids for 4-6 weeks (he was a big fan of anadrol) while training hard. Go off while still training hard for two weeks. Then dramatically reducing training.
He would do this when he wanted/needed to look the part. Until in the end he actually stopped caring as his reputation in his circle was enough to give him credibility during his seminars.
If it were not for these issues, could he have looked like a high-level bodybuilder? No (although he told me, at the height of his career that he would like to do a show, it never materialized). Not because of an incapacity to build muscle, but because he just didn't have the structure.
He also liked to train for strength a lot more than for hypertrophy. He always joked that his average rep number was 2.7 reps per set. Which, while an exaggeration, was not far from the truth. And we do know that it is not the best way to build maximum size (and it's a good way to get those injuries if done all the time, especially with the structure he had).
Your general point tha some people just don't have the genetics to be pro-zie despite all the knowledge in world is still true. I just wanted to add some context about Charles.