That is under the assumption that Sony and Microsoft, the owners of the Xbox and Playstation platform, agree to allowing mods in the first place. They were extremely skeptical and had to be convince by a multimillion company like Bethesda to be allowed mods for their games. So what makes a small IP like Taleworlds think they can have a chance to even talk to Sony and Microsoft?
And even after that issue is resolved, porting a game to console is extremely hard.(See Nier Automata, and Monster Hunter on PC right now, buggy as ****). The liability of ensuring that a console port will work for mods will fall in the hands of modders, and I imagine that most won't even bother.