"I wonder if this would also curb the used game market"
This is what they're ultimately after, imo. The more and more I think about it, it's turning into more of a control issue rather than trying to curb piracy. I think they realize trying to really stop piracy is a lost cause but used sales is something they can stop. I also wonder if the PC's is being used as a test market to see what they can get away with and it will eventually roll over to the consoles, where the real money is these days.
As to the PC gaming market...I really hope we'll see a rise in the indie developers and have a rebirth of the scene with some original and unique games like we used to see.