If Sena were to offer a standard mount that they would ensure would be available for the foreseeable future, helmet manufacturers could design the speakers and microphone into the helmet, and Sena would sell the bluetooth device. The SF mount would work well for this and would ensure that a lot of people would be buying the Sena units (since they would fit the helmet) and the other manufacturer's helmets (pre wired and easy to install).
An additional benefit would be that you would be a lot more likely to upgrade units. I have several helmets, and I resisted upgrading because I would have to rework all my helmets. I did upgrade from the SF2 to an SF4, and really appreciated that it was just swapping out the unit, no redoing the wiring and mounts, and I didn't have to buy new mount kits.