I think I would agree with the comments that suggested breaking these votes up into broad categories in the future… not sure what groupings would work best, but I also agree with the comment that suggested broadening the appeal of historical kits by including fantasy/sci-fi bits, so perhaps the groupings might look something like…
Sword-and-Sorcery and Ancient/Dark Ages/Medieval/Renaissance Historical
Steampunk/Clockpunk/VSF and Napoleonic to Victorian Historical (ACW, Western, etc.)
Early 20th Century Pulp, Noir, Dieselpunk, and Historical (WWI, WWII,etc.)
Future/Near-Future/Apocalyptic Sci-Fi and Modern Historical
Deathfields and other Historical/Speculative Fusion (for those Samurai Elves and Space Romans that don’t quite seem to fit in with more traditional sci-fi or fantasy games)
I might be reading the audience all wrong, but it seems like there’s a ghost of a chance of historical/speculative crossover/kitbash appeal within those brackets (for example, those Dark Ages and Medieval historicals can appeal to fantasy gamers, and some fantasy kits might even appeal to historical gamers – might be able to market medieval kits with alternate head and weapon bits that would appeal to both markets.)
But, I don’t think that you’ll find many WWII gamers (for example) getting excited over space pirates or (futuristic) modular robots, and there’s only so much you can do with ideas outside of those brackets before you lose a genre’s/era’s dedicated audience.
Similarly, in my experience sword-and-sorcery gamers will gladly consider medieval historical models, but tend to lose interest really quickly when faced with some version of fantasy that strays too far outside of a generic fantasy sword-and-sorcery setting (something like steampunk fantasy or fantasy dinosaurs can be surprisingly hard to sell as a concept to generic fantasy fans!)
Those brackets might also define a rather surprise spin on something that seemed predictable on paper: those modular robots might have more fans among WWII gamers than among futuristic sci-fi gamers… maybe a modular robot kit with bits styled after the mechancial-men of old sci-fi serials and comic strips might be more popular than one styled after, say, Terminator or Star Wars droids, with your modern/futuristic gamers preferring to focus on modern insurgents or space-pirates…..
Anyway, pairing speculative genres to similar historical genres that way might help suggest some possible ways to please two similar audiences with one crossover kit, and might also help to fill out the product lines a bit for those customers who keep complaining that their favorite product line is being neglected with expansion into new genres.