"Can someone please tell me why Zeiss, Contax, Rollei, Leica, Voitander, Linhoff, Schneider etc dont all band together and create a new 30mm x 30mm specification for lens mount and film/digital backs (ala the 4/3 format by Olympus, except a larger sensor size)."
Remember APS? Kodak disc? The 110 format? Betamax? The compact cassette?
Voigtlander is owned by Cosina. Rollei is Samsung. Contax is Yashica which is Kyocera which may not be anything before long. Leica is controlled by Hermes and it's on the ropes financially. I don't know about Zeiss, Linhof or Schneider. But what's in it for any of them?