Generally, the games with mods as bad as you say that barely work and take a shit ton to even get that far are already broken to begin with and the mods just reflect the shit code. I was able to teach myself to mod Darkest Dungeon because its a solidly and simply built game and that made it easy to mod top to bottom.

The Free Market made Bethesda one of the biggest video game companies despite them actively releasing nothing but barely functional broken games that they outsource fixing onto mods. So that isn't something missing from this problem.