Well I respect your opinion but I don't believe strength has much to do with size.
Also the 575, question is at what point did he do that?
Its a known fact Zack started mega abusing PEDS from early age and I am on my first ever only cycle.
I think you are right about structure etc but if you look at Zack's early pics his structure was really not that great, he just had good arms.
Fundamentally, I believe it comes down to individuals response to gear and genetics and I don't think you are in position at this stage to right me off and say "oh it will never happen"...maybe it will take longer than 1 year but it WILL HAPPEN, question is to what extent etc.
Look at Rich Gaspari (one my favorite bodybuilders) he really did not have great structure or genetics but it happened.
Anyway I don't even want to get into full on bodybuilding, I want to do physique and for that I think I would be ok.
Most pros have been training and juicing for many years.
I used to think that if I trained long enough,I`d look like Arnold.
It doesn`t work that way.
Just keep training and juicing for 10 or more years.....if you`re still training by then that is.
To look at a pic of Kahn when he was younger means jackshit as far as you and your bodybuilding success or failure goes...trust me on that.
Best bet is to just try to keep progressing as much as possible over the years...........and oh yeah,sometimes life gets in the way.