In regards to the "used market" debate, I find it interesting that no one has brought up the "First Sale Doctrine." I included the Wikipedia definition below.

The first-sale doctrine is a limitation on copyright that was recognized by the U.S. Supreme Court in 1908 and subsequently codified in the Copyright Act of 1976, 17 U.S.C. § 109. The doctrine allows the purchaser to transfer (i.e., sell or give away) a particular lawfully made copy of the copyrighted work without permission once it has been obtained. That means that copyright holder's rights to control the change of ownership of a particular copy end once that copy is sold, as long as no additional copies are made. This doctrine is also referred to as the "first sale rule" or "exhaustion rule".

Therefore, there is nothing "lawfully" wrong with the "used market" per say.