No need to shut this section down, itīs not like it takes away resources from the [PAID]-board.
As already said, no replys in the topic itself isnīt necessary an indicator for lack of interest. I would say quit a few artist work for free on smaller projects all the time, but it is understandable that artist will work only on projects that are interesting to them.
Meaning it is the job of the topic starter to create interest for their game and itīs also important to think in realistic dimensions here, It is highly unlikely a good graphic artist, who can usually find paid jobs, will work in their free time on some mmorpg or something along these lines.