You've had your money for our purchases of Skyrim and its DLC already, Bethesda, and Valve are the ones who have to pay money to keep the Steam Workshop operational, maintained, connected to the Internet and hopefully policed.
Which begs the question of where your share is going, especially given how much money you're making off someone else's work.
How much is going toward new or unannounced products?
How much is going toward developing the Creation Kit so it isn't a bug-ridden, crash-happy and unnecessarily-obtuse mess?
How much has been ring-fenced for ESO or other existing products?