glblanchard wrote:
To answer your question, the reason lenses cost so much is that people will pay it. But all in all, I think today's photographers are a bit smarter, and can see the differences in a good lens and a lens that costs a mint because of it's brand name.
In the 1970s a company (I can't remember the name) made an f8 "Girl Watcher" lens. 500mm and cost about $70 and produced remarkably sharp images. It didn't fare well because it wasn't Nikon or Leitz.