those guys can give all they want for 5 sets of 5, but the fact is the human body is capable of enduring ALOT more than that, of course your last 5 sets of you 60 set workout you may not be using as much weight but you are still going to failure and its still a fuckin challenge.
you cant honestly beleive that 5sets of 5 at 100 % intensity is equal to 60 sets of 5 starting out with 100% intensity down to 80% even remotly compares to a low volume workout bro! you cant compare!
Sure, the human body is capable of dragging out a workout for a huge duration, but the fact is our goal is to build muscle. And our muscles only require a short amount of time resisting against intense muscular contractions before the growth process is activated.
While weight training for the hopes of being rewarded with optimal increases in muscle mass, more is not better; less is not better; the precise amount required is best.
Compare the stress of exercise to other forms of stress. For example, the stress of friction or sun exposure on skin. A precise amount of time is required before good effects (overcompensation) of this form of stress are experienced, from the development of calluses to a nice tan. But too much exposure and the bad effects (decompensation) are experienced, such as depletion, blisters and burns from the sun and blisters and loss of tissue from friction.
Now compare to exercise. The precise amount of exercise (overcompensation) and you experience gains in mass and strength. Too much exercise stress (decompensation) and you lose mass and strength.
I've overtrained and lost progress from overtraining with 15-20 sets before and 60 is something I wouldn't even dream of trying.