Or interface components at the assembly line it could be dicey.
I agree with you though, ideally it'd be as simple as installing the camera module and plugging it in and maybe add light bulbs to the side mirrors and boom...done.
But let's say the blind spot system comes with a different dash cluster option, then you are looking at a dealer software change at best.
But my guess is that of he can source the parts, he could make it work.