Steam has done the inevitable and launched paid mods with Skyrim. However, the terms are not necessarily to the benefit of modders.
As of today, 19 mods can be purchased via Steam to play with Skyrim. While some fans are worried that this could mean a drastic shift in free vs paid mods, it should be noted that the modders will only get 25 % of revenue.
Modders have some control over where the 75 % goes, as donations to entities like Polycount or Blender, but for the most part, that amount gets pocketed by Blizzard and Steam, and we don’t know how the amounts are broken up.
Ultimately, the system has been geared to benefit Valve over their users, but maybe this time these users won’t be cutting them slack for it.