Well... I didn't say "time under tension". I said tension x time under tension. It's the integral. So high volume 50-70% can equate out to medium volume 70-85% for hypertrophy, all other factors being equal.

I'd guess that drugs come into the equation if you were training around pro bodybuilders and that unlevels the playing field between each person because of how much they might have been on. And amongst the pro's, you're going to hit those genetic Mentzer-like freaks that can somehow grow on 45min 3x a week.

100% agree that drive and intensity is key, and there is more than one way to get big from a program POV.