A lot of mods are followers and reskins. most of those follower mods are pretty standard easy to make stuff. until you get into stuff like the super best friends followers mod. Do the best friends get a cut of that cash? Its their voices and likenesses used in that mod, shouldn't they be getting something if that mod suddenly has a price slapped on it? What about mods that use someone elses meshes and textures? Lot's of mods out their that are just modders resources.
Mods that deserve cash are things like skywind. big mods that actually take a long time to make. The assumption that a bunch of people in skyrims community page is that most mods take a lot of effort and time to make. Ive made mods before, they really don't. My mods weren't much good, but they really weren't that much effort.
What if this stretches into other games? the one im most worried about is tabletop simulator. people start charging for mods for that, and suddenly berserk games gets slammed up the ass with cease and desists from the companies that make the board games people are uploading. at least thats what I see happening.