re: Sony to block second hand games on PS4

I wonder how big of an effect this will have on game prices going down within 2 years of release. I picked up assassins creed 2 for $20 last christmas and enjoyed it the same amount i wouldve enjoyed it if i got it on release day. Without a used games market what is gonna drive the prices of games like that down. I dont really buy used games because the price difference isnt very big, i have sold quite a few games tho