I get the low set thing but I won´t go under 2 sets, max 3 if motivated or just using say 2 exercises for a muscle group.
I mean you´re doing 4 sets for chest with different exercise  probably is enough if going to failure

It suits my personality.  I hit it hard to exhaustion and the workout took something like 40 minutes. When I try volume it just feels weird stopping when I could get more reps. I know some volume guys doing something like this to exhaustion.  First set might be 25 reps to exhaustion. Second set to exhaustion taps out at 18 reps. Third set to exhaustion taps out at 13 reps. Last set is 8 reps to failure.

The traditional volume is doing something like 4x10. First set is 10 reps but could have gotten 15. Second set is 10 reps but could have gotten 13 reps. Third set is 10 reps but could have gotten 11 reps. Forth is failure at 8 reps.

Some volume guys do this to increase the intensity by using short rests between sets to rush the failure point.

Try it sometime.  Say for barbell curls. Do a non taxing warm up set. The key is non taxing.  Then load the bar up and do reps till you are blue in the face and if someone offered you a million you couldn't get an extra rep.  No way could you want to do another set nor could you with the same amount of reps. Truth be told multiple set might be a more optimal way to train but if you could get 95% out of training with that one jagged set and you're not a pro bodybuilder why wouldn't the majority do it? One reason is it's too hard to train that way.

Brian obviously missed that last two Olympias

It's more because he knows jack shit about bodybuilding.

3 of the last 4 men to win Mr O were around 5ft6 or 5ft7 and were far from "mass monsters".