Hi Edgar
Probably because this SPAD is in no way comparable in quality to CSM products and it requires significant improvement work.
Concerning the Voisin, what reasons prevent you from making your dream come true? 
The wingspan is a major challenge?it's quite significant, and I'm concerned the wings might sag, wings are not rather thin.... Another issue is the tailboom; it could be heavy, which raises the risk that the model won't stay on its four wheels. These structural concerns are what hold me back for now.
Regarding the SPAD, I think morane hit the nail. The SPAD is generally a difficult kit to build, I am afraid.
I see also all your points on the Voisin. But I built WNW?s Fe 2b some years ago. Its wingspan should be almost en par with a Voisin. The wings do not show any signs of sagging. The same on the tailboom question: no deformation after years. I praise injection molded plastic 
Adding some strips of lead into the bottom of the nacelle and adding weight to the engine would be a possible solution for the tail-sitting issue. Maybe you could do a later Voisin with in-line engines that would cover more lead weight than the radials of the III/V? Or filling the tank with weight? All given as an advise in the instructions for each individual modeler.
I am neither a material specialist nor have I any experiences with injection molding, but I would be happy to support your dream to release a Voisin ? it is also mine
Thank you, Andreas! However, there are some notable differences between the two aeroplanes.
Wings
The FE 2b has a three-section wing design, meaning it needs to be built in three parts?similar to how you approached your FE 2b model from WNW. In contrast, the Voisin's wings consist of two halves joined at the center. This central join could create a weak point, potentially compromising the structure's stability. I believe this isn't an issue with the FE 2b due to its dihedral angle.
Tailbooms
The FE 2b tailbooms are comparable to those on the Caudron. These booms aren't simply suspended in mid-air; they provide an additional stability point, reinforced through the tailskid. On the other hand, the Voisin's tail is entirely unsupported, essentially "hanging" in the air. This means the tail needs to be as lightweight as possible to ensure the aeroplane can rest stably on its four wheels. Additionally, the Voisin's hollow fuselage compensates by distributing weight toward the nose.
I'm not saying these challenges can't be addressed, but they certainly add complexity to the process.
