@Angelo Farina you bring up some interesting points. I wasn't around (as a diver, at least) in the halcyon days of yore, so I can't comment on the training back then. I have heard stories of it, though, and a few things come to mind. First, the hardcore training of old definitely seemed to have some items/skills in it of dubious value.
Yes, some parts of these very long courses needed to be cut away or to be moved to additional and optional classes.
The 2 months with the ARO in the pool was the most controvertial part, as no one was using this obsolete CC rebreather anymore for diving in the sea, it was used only in the pool for training. The good thing with the ARO was learning breathing control and neutral buoyancy and perfect trim (which was VERTICAL with the ARO).
It was also used for teaching efficient hand sculling (not paddling), with the same movements used in synchro swimming and water polo, which was considered the basic propulsion to be used inside caves and wrecks.
I was one of the (young) instructors pushing for removing ARO training and replacing it with BCD training. In the end we succeeded in this..
Second, the physical fitness and mental toughness required for some of the old training acted as a filter of sorts on who decided to pursue dive training in the first place. I'm guessing that students - and thus, ultimately, certified divers - were disproportionately young, fit men.
Actually not. We had just a 30% succes rate because students were often over-the-age, fatty, unsporty, with bad mental habits and definitely not properly motivated.
More than half were females, diving was fashionable at the time, and those girls and ladies wanted to pursue this sport for being photo models underwater (or photographers).
Lotti Haas was their role model...
I remember a class of 20 where ALL students were females... Only 3 were certified, the others were just posing.
Third, and very much related, is that most students and divers were people who were serious about diving.
Again, absolutely not. This was true only for those 30% who managed to complete the course and being certified.
But then PADI arrived, and we have seen all those students who did not pass the CMAS course being happily certified by PADI and proudly showing a number of specialy badges glued to their suits...