failure training isnt necessary, and it stops people from doing enough volume. "high" (relative term of course) volume is the best for growth (most of the time, as training has to be varied to some degree)
Your opinions only; i completely disagree no matter what the protocol, and have done both high-volume and now moderate volume training. In both cases, the muscle reach the same point, with resulting DOMS. This can be done with less sets if the training is more efficient = better exercises + intensity.
As i said, most BBs are very conventional in their thinking, therefore volume will be part of the winning formula, which doesn't mean it's necessarily an essential ingredient. Not the same thing.
Overload, baby. That means intensity, either exaggerated intensity as in HIT because there are very few sets to spread it out over, or intensity spread over more sets, within volume. It's a continuum, based on numbers of sets.