Thats because the game lacks offical mod support. As in something like the bethesda games where any external file overrides the file in the games archives that has the same name. Want a better texture on something? put it in the data folder following the same file directory path and name and it'll be used over the one in the base game automatically. This is what 7dtd needs, the sad thing? I dunno if unity can even do it. Currently to mod textures or models etc, you need to decompress the games archives, put in/replace the new/old stuff then recompress it back up. I know you can inject like icons and such via the mod folder, but doesn't seem to work for textures or models.
The mods we have now are pretty basic, if they had access to it like the bethesda games, we could have some pretty impressive mods. I mean some of the ones we have now are really good, but if the game had proper mod support they could be even better. Not to mention the graphical improvements modders could do if it was easier to implement them.
I don't know if unity just can't handle that kind of modding support, or if the devs of 7dtd just don't seem to want to or aren't able to put it in.
