Hiver ive already pointed out that your only example that of the upcoming UT game is a broken one the engine that will be used to make content is a proprietary engine that you will have to buy into cheap as it may be its still a cost based model of 15 dollars per month. Plus Epic then retains the right to further monetize your work and as i have already stated its the "cleanest" way of doing it and the one method i have no issue with.

However taking a free modding tool for a proprietary game to make content then sell that content using any scheme seems disingenuous and frankly i can see no examples in the world where that has ever been done successfully and as i said it is also legally difficult.
Why is Epic able to do it? because they have control of that content from beginning to end even though in all honesty i see this blowing up in their faces eventually time will tell.

Furthermore this charging for mods upfront i will not agree to no matter what scheme your suggesting (in this example colluding with larian), the simple fact of the matter is it would be charging for mods upfront, i don't know how you believe that your carefully worded side step changes that on the user end of things you are being charged upfront. there are quite a few studio quality modifications for skyrim another community that ive been involved with faalskar being a very good example even so much so bethesda gave the creator an honorable mention but in the end it was still a modification of their game using their modding tool.

Furthermore ive seen community packs for games included in official content for many a game but it was never ever charged for the only game your clinging to with any iota of precedence in this scheme even working A: hasn't been released yet B:Still requires a paid for engine so my argument still stands no developer has ever allowed monetization of a "mod"

and one can only judge the future based on what has happened in the past can larian break the mold? sure they can, have they? no they have not, do i want them to? hell no! i love this game its the only rpg since skyrim ive found with any promise.

And in concluding every mod hoster meaning third party sites that host game modifications have rules against monetization nexusmods, modsdb, steamworkshop, meaning paid for work could not be posted to any of them which further cements my point that every major name in the modding community is firmly against the idea of mod monetization in anyform and since larian has integrated steam workshop i believe they have to adopt SW's policy yes you can host elsewhere but once again a whole other can of worms and headaches i doubt larian would want to take on.