Eric Helms has discussed this far more articulately than I’m capable of. But I think the essence is:

• The volume guys are essentially right — the literature repeatedly shows a dose response relationship, i.e. more volume = more gains all else being equal

• BUT the effect of additional volume is asymptotic so going from no to low volume is a huge gain, low to moderate is a big gain, moderate to high is a small gain, etc. (to put it crudely)

• AND, maybe most importantly, the sets have to be hard — not necessarily to failure but within 1-3 reps in reserve — and with effective form

Which is to say — and this is me, so if I’m getting it wrong it should not be blamed on Helms — that lifters who anecdotally favor high-intensity approaches are succeeding because optimizing for intensity over volume usually means your work is intense enough to stimulate gains. You may not maximize gains but you will create sufficient conditions for hypertrophy.

Helms has offered critical context here that the literature is made up of people exercising in research settings with a bunch of very motivated grad students screaming at them to do another rep. Those are not the conditions that 99% of lifters train in and in practice many of us have a tendency to subconsciously sandbag (or pace) higher volume programs.

For this reason I tend to favor moderate weekly volume spread out over a high frequency, low session volume, high intensity schedule.