I support selling mods. If people want to put out mods for free nothing is stopping them and the devs already effectively do this, they just called it "DLC". I have zero problem paying money for quality mods.
Like right now I'd like a mod that: Allowed me to choose between 1-4 characters, allowed skillbooks at every level, one for each "main" character, and increased the character options as far as appearance went. And they promised to continue to update the mod to keep it current for at least the next two years or so.
Let's say someone offered a mod with all of those features. I'd have no problem paying 10-15 bucks for it.
They invested know-how, time, and skill into a project. Why *shouldn't* they be compensated?
A mod marketplace might do WONDERS for a games longevity.
Look what it did for D&D.
They had an open source game in 3.5 and that system and those books have become such a juggernaut that the company that produced them is having a hard time reigning it in... creating the monster that could supplant them in the future because they stupidly abandoned their own system (Pathfinder).
If Larian said "Want to sell your mods on our marketplace? No problem, we take 10% of the sales and you get the rest" I can GUARANTEE YOU the result would be stunning and high quality mods.