I have owned a lot of Olympus cameras over the years. Always good optics, sometimes a little too lightly built, but excellent designs. I doubt the OM-X would have been a runaway success like the OM-1, OM-2, etc were though. Just like with the Rollei SL2000 and SL3003, the design is complex and has to be very precisely made, which means costly and requiring more thought and understanding in use.
Victor Hasselblad made this interchangeable magazine design a reality with the Hasselblad medium format SLRs, and it works (and was widely copied) in that larger medium-format context. Remember also that, hmm, was it Exacta or Contax??, had interchangeable film magazines for 35mm SLRs and, while they are marvels of engineering finesse, they ultimately were not anywhere near as successful as unit body designs that supplanted them as the 1950s-1960s progressed.
G