The way things are going they may contemplate shipping the backs permanently attached to the cameras - less wear and tear, less cost to manufacture, less dust ... avoids users being able to take even better pictures by putting their backs on view cameras, increased sales of the HTS adaptor, and increases dealer's profits for cleaning sensors... how often do you take the back off yours?
The benefits of a modular professional system normally include:
Easy upgrade path for any component (e.g. new back on old body, without return to dealer)
Interchangeability between components manufactured decades apart
Are the backs more reliable than the Camera bodies? should we all carry complete spare systems? (I intend to buy a 39 Mpx back for my ELD/flexbody system... so I would then have a complete spare system for about £8k)
There are benefits to modular design, but it is not without cost;
Since modular design by definition must maintain compatibility of existing equipment to function, it must forfeit some technology gain that has developed since the initial design of the system components. This is exacerbated when certain components of the modular system are unable to accept any technology advances and begin restricting the system from offering solutions that compete with newer systems using advanced materials, processes, and functions.
This may explain why do not see modular design in modern 35mm DSLRs, Operating Systems and Applications, and now medium-format camera systems. Advances in technology solve problems that are difficult or impossible to address with conventional tools leading to HD-video in a Canon 5D, 16-bit editing in Photoshop CS4, and a motion sensor in the Hasselblad H4D.
There are practical benefits to a system that can adopt and apply advances in technology. In the field, I have upgraded firmware in many Hasselblad H-systems (H1, H2, H3D, H2F) enabling these systems to do more than when originally purchased. Field firmware upgrades (another advancement) are not just for the H3D - firmware updates that are beneficial for all Hasselblad H-system owners (mirror delay, battery status, re-program user/ae-l/mirror-up/stop-down buttons for custom tasks.)
Again, better to show you to remove all doubt.
John