I also have the Mentzer workout DVD (on VHS actually) and even that workout, made in 1999 I believe, has far more exercises than his Consolidated Routine. In fact, the workout he displays on that tape is actually something that I believe 'could' work...it's very demanding, and the supersetting of exercises and intensity needed are tough.
But even in that tape, there's no 'one' set. In fact, I count at least 3 sets for most exercises, sets which, for many if not most people, would constitute 'working' sets. But that's besides the point, call it what you will....Heavy Duty requires a hell of a lot of very hard work, and that's undeniable. And that's a big reason why most don't train that way, it's very demanding, taxing and brutal. And since you can get some pretty damn good results training other ways, that's the way most choose. It's the way I choose!
Interesting thoughts on this topic. I also think that if people did the real trials of many different styles, they'd find some benefit in ALL of them....many settle on 'best' being somewhere between where results, enjoyment and difficulty meet. Kind of like getting an education...sure, you could get a degree in 3 years by not taking summer holidays, but some folks like more laid back approach. In the end, you generally get the same result.