I did not say the above in absolute terms. I left room for the big guys that actually do train hard (as the guys you mentioned do). However I think we can agree that it is far from a NECESSITY since there are so many big guys that train without any intensity at all
I would just say that everybody has to listen to his body, but training smart trumps training hard.
Like you said before, I also know many guys that destroy themselves in the gym each and every workout to the extent that they are barely able to walk outside, and still get no results. My theory is when you overdo it, you tear the muscle even more down than you can rebuild with proper rest and protein afterwards.
Generally I'd say that most people with average genetics would probably do better without muscle failure at all, just that you can get the last positive rep completely yourself and that's it. But sometimes your ego dictates you to push the limits, and you again do things altough you know they won't help you.