Check your body temperature, Boltgun. Yeah a community provides assets and making some sort of a mod pack would be easy, but an original mod? Yeah, the basic engine, why would anyone ever use it for a mod instead of making a new game in unreal engine 4 (FREE, sort of)? The amount of work is close (ie. beyond insane for a single person, unless you conform to pre-packaged standard designs) but you can actually make money on it, and you won't be helping Firaxis to survive. Their games are crappy, Beyond Earth is worst so far, their only hope is modding community which can turn any crap into gold, for free, especially in the current age of easy-to-use 3d gfx tools and many unemployed people.