A very well written article, and I agree with many of its points.
I've been a manager for 2 different games companies in the UK over the past 6 years. One of them was a big chain, and I currently manage a store for an independent company.
In my opinon (I've got no access to the company's financial information or anything like that), the independent company that I run a store for now, might not be open if it wasn't for the preowned games market. Either that or they wouldn't be doing as well. New games don't make all that much profit for the smaller companies, as they cannot buy in bulk as much as the larger chains and supermarkets do. And some publishers are notorious for having high cost prices on games, and only offering discount to companies buying a bazillion copies for their 300+ shops.
Here's an example. A new game is released on the 360, and the cost price to the independent retailer is £32, seeing as they may be buying 30 copies (depends on the popularity of the title/amount of shops they have). First of all, since we're in the UK, we have to add VAT on to that before looking at any sort of profit. VAT's 17.5%. So already we're up to £37.60. The game goes out on shelf at £49.99, looking to make the independent retailer £12.40. Nice one, you may think.
However, the chain stores and the supermarkets have already gotten a better deal on the game, and are able to put it out on shelf at £39.99 and still make a half decent profit, seeing as they're buying thousands of copies. From this one of two things will happen, either the indie has to lower their shelf price in order to stop people just walking down the road and buying it, making them a paltry £2.40 profit. Or, they leave it at that price, and it sits there until eventually they're forced to drop it further and sell it for a loss just to get rid of it.
Now I know I've used a costly example, and to be fair it's the "worst case" scenario. Though you can still apply the same logic to any cost price - if it's £25 for the indie then the chains will still get it cheaper, it just means it may be a game that has an SRP of £34.99 instead. And, a lot of companies (mainly supermarkets, but some of the larger chain stores too) will put out a game on shelf that they're making pittance on, in a bid to get the customer into the store in the hope that while the customer's there, they'll spend more money on other things with a higher profit margin.
Preowned games are a good money-maker for the smaller companies like the one I work for. Also, I do agree that a lot of people can't afford to go out and buy a brand new game, so they'll either buy the preowned one or just not bother.
What I see a lot of too, is people coming across an older title (say, Rainbow Six Vegas, just for example) for around £15, and buying it because it's cheap and they want to give it a go. Then, that customer comes back a few weeks later a preorders a brand new copy of Rainbow Six Vegas 2 because they like the first one so much. Then they branch out into other Tom Clancy games like Ghost Recon and the likes.
Preowned games do a lot less harm to the industry than most people think. As I've said in a previous thread, I remember trading in Mega Drive games about 14 years ago to get the latest one, and have been trading in games ever since. If the games industry is doing as well as it is, after at least 14 years of trade-ins and preowned games being around, then it certainly can't be a bad thing.
Lastly, apologies for the huge post...I tend to ramble a little...