The real cost of used games is the damage that is being 
  wrought on the creativity and variety of games available 
  to the consumer

Yeah, because it's a well known fact that being able to resell your used book has for ages 'damaged the creativity and variety of books available to the consumer'. Our writers have been severely creatively impaired and there are hardly any books available... oh wait, that's actually not how it is.

Any measure to prevent the ability to play 'used games' will be reverse engineered and circumvented. Combined with the first-sale doctrine, this will always allow the reselling and playing of used games. If you don't like it, why don't you, you know, think of a creative solution?