I am surprised kit boat building isn't all that strong. The kit plane market seams to be healthy. Why not just buy a FG hull, deck, and liner module and put it together yourself with you doing all the mechanical, woodworking, and plumbing? I believe some early Flickas came that way. Why not now? Is the bulk of the labor just in laying up the glass? If I can buy a all metal plane kit and just spend 500 hours riveting it together, why not take a pre-made hull, deck, and liner module, poured keel, and do the rest? Can't be all that hard to put one together.
One very important reason why boat kits are not as popular as kitplanes- size.
A kitplane can be shipped on pallets, weighs well less than half a ton and can be handled by any freight company. Then, once the new dream is delivered, the builder can build the subassemblies in the average garage , shed or basement workshop, and do final assembly in the driveway. Kitplanes are also relatively short, allowing assembly in a standard height garage.
On the other hand, a 30 ' hull with a 9' beam would have to be shipped by dedicated truck, would likely require permits, and then would require a space with a substantial amount of square footage and high ceilings to finish construction, or the builder is limited to working on fair weather days.
This may explain why small boat building is alive and well, but for every dozen dinghies being finished in garages across the continent, there is one more ad on craigslist for an unfinished 30 ' plywood dream. Ever notice that most of the "free boat" and "cheap boat" ads in the back pages of good old boat and woodenboat magazine include the phrase "lost storage"?