There were many camera features and designs by 1971 which would only appear later in more camera modes. There were prototypes of automatic focusing (Leitz), "still video" or digital imaging (Kodak), electronic exposure control for Aperture Priority automation (Zeiss Contarex SE), solid state shutter control and metering (Yashica). It was known by then that camera shake was a primary cause of unsharp photos. By transmitting information from the lens to the camera body, some of these problems could be avoided. The camera had to know the focal length of the lens attached to either set an appropriately high shuter speed or to at least warn the user. Konica used a mechanical system to allow the user to see the maximum aperture of the lens attached. Things were very much up in the air on 1971. The process of designng a new camera was time consuming and if the manufacturer waited too long to bring out a new model it might be outmoded by the time it appeared. The first Canonflex model appeared in 1959, the same year as the Nikon F. The Canonflex line was already out of production by the time the Canon FX appeared in 1964. The Nikon F proved to be a very adaptable design, going from a meterless model to a selenium meter model to a CdS meter model, ending with the FTN, which overlapped the F2 for a short time in the early 1970s. The F had no metering with Waist level or Action Finders. In this sense the Canon F-1 of 1971 was more elegant. It had its meter built into the body (except for the Booster finder) and allowed the use of the Speed Finder with metering. By the time the Nikon F2 came out with its DP-2 and DP-3 (solid state CdS and Silicon) meter prisms, its metering was more advaced than Canon's for several years. It was no longer worth Canon's efforts to improve the in-boy meter of the F-1/F-1n and it waited until 1981 to introduce its F-1N with an in-body Silicon meter. During these years Canon offered the AE-1, AE-1 Program, A-1 and other A series cameras. Eventually Canon even made AF lenses with their own focusing motors in FD mount. Canon, when it introduced the FD cameras and lenses, was determined to keep up a technological lead rather than fall behind. The FX had an external meter in 1964. In 1965 the Nikkormat FT had TTL metering and in 1966 the Minolta SRT-101 had it. In that same year Canon finally has TTL metering in the FT QL. The problem is that the SRT-101 had full aperture metering while the FT QL still used stop-down metering. In 1968 Konica had shutter priority automation, full aperture metering and TTL meterng. It would be another three years before Canon had TTL metering and full aperture metering with the F-1 and FTb models. Automatic exposure was a clumsy affair and could only be accomplished (with a fully interchangeable lens system) by Canon with the F-1 and the Servo EE finder. A purpose made auto exposure model did not appear until 1973 wth the EF. When you think about it, Canon went a long way from the time the FD mount appeared in 1971 and when the F-1N was formally discontinued in 1996. It's true that when the EOS 620 and 650 models appeared in 1986 Canon clearly aimed its efforts at the AF market and only a few ew FD lenses appeared after that. This is just what happened to Minolta in 1985 when the Maxxum 7000 appeared. By 1986 when the EOS models had appeared the lens mount was changed and when the user set an exposure mode the lens transmitted its focal length and minimum and maximum aperture settings to the body. With enough time Canon could have adapted the FD mount to transmit some of this information. The EF mount had many benefits including the wider bayonet. This allowed faster lenses to be developed more easily. Eventually Image Stabilization appeared too and over time keeping the old FD mount seemed like it just wouldn't have been able to handle all of the new technology. Early in Canon's FL period (1964 to 1971) Canon saw the need for full aperture metering and was already working on the FD system. As a Canon FL/FD collector and user I still enjoy using many Canon manual focus cameras and lenses. I am partial to the mechanical models. I have no doubt that Canon could have developed the FD mount further but after a certain point it was no longer practical.