Is Fuji keeping its communication specification to itself to protect lens sales? I have a Canon system and would rather not duplicate lenses. The Fotodiox Fuji-Canon EF lens adapter looks like something not worthwhile. If you look at the Sony side of things, a variety of E-mount adapters that control AF and aperture exist. Why not for the Fuji?
I don't know whether Fuji refuses to give away or license their lens specs to others. They do have agreements, though, most notably with Zeiss. Also, the Fujis can use certain third-party lenses from Leica, Zeiss and others via adapters that provide good functionality, and adapters exist from other manufacturers. Any lens manufacturer will need to decide whether they want to license the required technology (if available), or reverse engineer the lens interface and potentially run into IP issues.
I think, overall, one cannot expect lenses from other manufacturers to work on a given body. If they do, I would consider that a bonus. Of course, if you can use your existing lenses on a different body, then that may affect your purchasing decision. Fuji, and everyone else, is aware of that, and they take that into account when they design and market their systems.
