yushire, you are simply mixing two different things. UGC doesn't have anything common with modding.
The UGC that Malstrom hates is the idea that developers could just release "construction sets", and "editors" instead of games, and the gamers will all entertain themselves by creating stuff,(more like putting stuff together) or by watching others' stuff.
Modding is popular, because the base games themselves are popular, people love them, and some talented people love them so much that they even make meaningful, enjoyable content for it, also using their programming skills to make it surprising.
UGC games like Wii Music or Spore fail hard, because they rely on "here is an empty game, do something.". For example in Spore, (the one I'm familiar with), there are hardly enough talented fans to create meaningful content, but even if there would be, it would be anything but meaningful. They could basically change the location of the body parts on a creature, or the coloring of a house. No one will feel thrilled for exploring an universe full of purple box houses, yellow pyramid houses, green box houses, yellow sphere houses, spotted pyramid houses, spotted box houses, and lots of penis creatures. (seriously, lots of them.)
They would rather pay for professional content, or even semi-professional mods.
