Well, watercraft 3d models are always expensive because they are very difficult to model even with blueprints. Besides, most models are CAD transpositions with lot of triangles and bad topology, which means you cannot use it with a lower subdivision level and will give you troubles if animated. Add to that the interior, the furniture and the huge list of materials (I sell on Blender Market photorealistic materials collections, usually ten materials for 29 dollars) and you' ll have quite a value packed in a single product!           

Coming! There are some issues with the physically-correct approach in Eevee materials, but I am studying how to overcome them. I don't want to put up a model that strays too much from the Cycles version, so I am working hard to translate materials as close as possible