Many of us have purchased Maker Kits and have many spare basic parts lying around. How about supplying upgrade kits for the larger models, i.e. black widow, T.R.U.C.K etc. These kits would only supply the parts which are not supplied in the maker kits. Possibly also excluding motors and boards, Most assembled models are not usually kept assembled forever and can be used in other projects. I often thought that this would have been a good strategy for Lego and allowed our younger generation to save up and get kits faster.
There are many variants of what people have left of parts, and many parts will probably be needed to complete a larger model. We will sell 3D printed parts as spare-parts, but it will normally not be worthwhile to buy these to complete a large model.
But we have open instructions and parts lists, but people must count what parts they miss themselves. Many of the items like motor etc. are industry standards, and can be used to experiment using in big models. One can even use other controlling electronics than the RoboBoard X4.
Also we have open STL files for all special parts we supply. This can even be used by all that wants to print the parts themselves. And in your philosophy: We will sell the Spider and all large models coming, without the RoboBoard X4, power and battery. Thus a quite less expensive kit. Many people wants to experiment with their own electronics.