The economy is a part of it, but so is the fact that many of these venues were built only for sports with little local interest (like softball), and now have no use.
A number of Greek officials admitted to the AFP that there was a lack of planning, and no one considered what they would be used for after the Games.
Despite all that, many of the venues from the 2004 Games are still going strong. The Olympic Stadium, Olympic Village, media center, and a few small-scale sports arenas have all found tenants.
But still, the aquatics center, beach volleyball arena, and softball arena are all literally falling apart. In addition, the massive Helliniko Olympic Complex where many events were held has been abandoned, and is in desperate need of private investors, according to AFP.