That's a really stupid argument Neil.
Player made content is so rarely up to the standard of an actual developer made DLC, even for games that have been out several years like F3 or Oblivion there are really only a few mods that could be considered along side the DLC and even they are usually pretty limited in size.
Textures/models/fps etc maps yes, I agree generally mod communities do a better job but talking about bigger games like Fallout and TES etc? No, modders don't even come close to creating content that the devs themselves release.
It always surprises me when people pirate DLC, in some cases I can get it, stuff like Day1 DLC that they only release with pre orders or stupid little things like the Mass Effect DLC for guns and armor, but look at some of the F3/NV DLC, they are bloody amazing, adding dozens of hours of game play to already massive games. They went to the trouble of making a great game, they released a finished product, did they stop? no! They made even more great content to go along with a game which stands up perfectly by itself, they didn't just change the colours of a few items or add some pointless gimmicks, they added real engaging content. DLC like that allows Devs to make more money from a single game whilst not just screwing the fans, which I am all for.