Jumping into this without reading everything before (it's 6 pages and I have limited time!) it strikes me that THQ have missed the middle ground here.
Why not say that second-hand games will work online after a certain amount of time. So if you buy a second-hand copy of a THQ game a week after release you'd have to wait 6 months for it to work online. That means that you can buy a game and sell it on later and still have the game work fully but it also means that buying a game second-hand a week after release isn't as good a prospect as buying it new (which is what THQ want).
The point THQ need to get is that there are people out there who buy games
because they can sell them off once they get bored of them. At $60 a game, you are asking for a large sum of money for a game. There are lots of people who aren't willing to pay that much but who are willing to pay it knowing that in the end they'll only pay $35 because they'll sell it off later. In these cases THQ might not actually be losing money from the second hand market. In fact they might actually making money. If you make $60 from both people when neither of them would have bought the game at full price then you've effectively made the same money as you would have if they'd bought it 6 months later on sale for half price.
Without any sales figures it's hard to say if THQ are making money, losing money or breaking even on second hand sales. So do they have any to back up their points? Or are they simply making the same mistake that we've always lambasted RIAA and MPAA for in assuming that every pirated movie or CD would have been bought for the full price?
Anyway, if anyone has raised these points before just point me to an answering post.
