Why so? As far as I understand, Microsoft still goes with the templates their hardware OEMs already have: Surface is based on a tablet template, while Surface Pro and Surface Book are supposedly based on different laptop templates and the available options are thus defined by the OEMs. This also explains why the 'Pro' versions 1 and 2 had cameras inferior to the 'non-Pro' versions.
I wish Microsoft got their act together and gave more attention to design, while they are at it. If they are saying this is a tablet that can replace my computer, let it have what those tablets that can't have: cellular module. If it has a non-removable hard drive, let me have it in the greatest available capacity, sepecially while you already offer that on a lower-priced model.