If The Infernal City didn't sell well, then Bethesda has only itself to blame. I didn't see or read one article about the book's release on any site. I didn't see it advertised anywhere. Outside of people who regularly visit the site, I'm not sure anyone knew about it.
If you want something to sell, YOU HAVE TO PROMOTE IT!
If you want something to sell, YOU HAVE TO PROMOTE IT!
Agreed.
However, I think part of the problem comes with the fact that these "franchise books" (like the Forgotten Realms ones or the Star Trek or Buffy novels or whatever) tend to be rather forgettable, and because of this I'd imagine book retailers might be reluctant to sell books that they don't think are going to be popular.
Now, if they want to reach their target audience, why not sell the books at videogame stores like EB Games or whatever? Or how about comic shops? At least there people would be more likely to pick them up.