The Bethesda Blog has their side of the story regarding the launch of paid mods on Steam for The Elder Scrolls V: Skyrim, an announcement that has spurred considerable unhappiness in many circles. Here's a bit:

We believe most mods should be free. But we also believe our community wants to reward the very best creators, and that they deserve to be rewarded. We believe the best should be paid for their work and treated like the game developers they are. But again, we don’t think it’s right for us to decide who those creators are or what they create.

We also don’t think we should tell the developer what to charge. That is their decision, and it’s up to the players to decide if that is a good value. We’ve been down similar paths with our own work, and much of this gives us déjà vu from when we made the first DLC: Horse Armor. Horse Armor gave us a start into something new, and it led to us giving better and better value to our players with DLC like Shivering Isles, Point Lookout, Dragonborn and more. We hope modders will do the same.

Opening up a market like this is full of problems. They are all the same problems every software developer faces (support, theft, etc.), and the solutions are the same. Valve has done a great job addressing those, but there will be new ones, and we’re confident those will get solved over time also. If the system shows that it needs curation, we’ll consider it, but we believe that should be a last resort.

There are certainly other ways of supporting modders, through donations and other options. We are in favor of all of them. One doesn’t replace another, and we want the choice to be the community’s. Yet, in just one day, a popular mod developer made more on the Skyrim paid workshop then he made in all the years he asked for donations.