Well, I don't know anything about what old-time racers in Italy thought at the time.

I can tell you that my father, who was growing up on the other side of the Alps when these various derailleur systems were in development, though not a serious cyclist he was definitely a bit of a gearhead at the time. And he had a strong impression that hub gears were terribly inefficient. I don't know where he got this idea; but evidently he's had it since the 40's and he still brings it up today. Drivetrain efficiency is still something he considers to be important in bicycles and, despite this concern, has no hard data of any kind about what's efficient and not.

In another age and on another continent, Racycle made those bikes with the gigantic chain ring, not for use on a track or setting speed records behind a motorcycle, but because the giant chain ring was deemed more efficient; less energy was lost to friction between the plates of the chain. Again, drivetrain efficiency was of paramount concern to someone, though I don't know whether that was the designer or the salesman or the customer. And I suppose it must be efficient iin terms of drivetrain efficiency, though I personally consider optimal gearing to be far more important.