Second hand games market can mean the games stores make up to 10 to 15 sales from one game and make lots of profits from the reselling of the same game over and over. Only one new game purchase would have been recorded despite 10 to 15 purchases of that same used game through trades. Piracy results in 0 sales of the game due to games being leaked before launch and torrented online.
New games selling for a reduced retail value is better than a used game sale. Used game sales could be partially blamed for a reduction in new game sales which have sadly led to the demise of some game developers.
A good argument for the used game market here is that used games keep a lot of game stores in business. Major retailers as far as I know do not have used game trade and sell discounted new games. Specialised game stores and pawn brokers are the stores that rely heavily on the second hand trade.
At the end of the day what would you prefer a new game or a used game? I personally would want a new game and nothing beats taking off the plastic seal from a new game. I do not just buy any game only the best games are for me. Thank god for Metacritic/Gamerankings that give us all an idea on what games are hot and which games are not.