You are correct in your observation. The Aboriginal working Caucasian Ovcharkas, though large, were not as large as they are today. The city dogs are heavily inbred and crossbred with St. Bernards, Tibetan Mastiffs and other Mastiff type dogs to make them bigger. The original dogs were considered large - but not the giants you can see today.
It seems that there is a "separate" breed for the city and home .. and then there is the ultimate one for the farm and ranch where real work has to be done. In the 16 years I have been involved with the breed and in all my research and learning - it is quite obvious that the breed has taken divergent paths. Of the 7 that I have owned - Caesar and Cleopatra are the real working types. Serious, sound, and not large but - definitely the correct temperament. You may have seen them in the gallery.
There is a big difference between the two - and it it NOT good for the breed. We need to dogs to stay true to their working temperament and form since we know through evolution that "form follows function". Lets keep the COs real and true to their temperament.