Actually the early cd print runs when KQ5 and KQ6 were released (when the technology was 'bleeding edge') were more expensive to produce than the later cd print runs. That's one reason Sierra was able to get the $59 price point when other companies, especially console games were offering games for $10 less to almost half that.
Even then, and yes this is anecdotal, you can go online and find plenty of 'used copies' of KQ6 and KQ5 cds as well... 35-40 copies of KQ5 for example... More copies than they offer used for KQ7 and KQ8 ironically enough... Frankly, that's how I've seen it in the few places I know of that sell used games... Lots and lots of copies of any of the KQ games...
Also it isn't recommended to buy early used copies of KQ7, as they are bugged high heaven, windows 3.1 only, and certainly require alot of patching.
Yes, its anecdotal, but there are alot of people that absolutely hate the KQ5 cd because of the poor voice acting! It may be a coincidental that in some places there are more used copies of the game because of that. There is certainly not proof that is the reason why there are alot of used copies of KQ5...
Personally I'd think the glut of collections of many types might have to do with the large amount (technically not really that large amount when you consider that originally they sold for at least 300,000 copies) of used copies of any of the games. However, there really aren't that many used copies of the collections out there. Which may or may not point to people keeping collections rather than the individual games.
Also, its not exactly 'fallacious' for me to say that I have never seen any traditional 'game stores' that sell pc games where I live, as there aren't any stores that sell used games... Which is likely the same reason MusicallyInspired said nearly teh same thing! In no way did I say, there are 'no examples' of such (just that I've never seen traditional 'game stores' sell used PC games), which you seem to be accusing me of...
Also I specified and said I don't know of any 'game stores' that sell used games... You mentioned 'half-price books' which is of course not a 'used game store' but a used books and other things store...... For that matter I've never seen a Half-Priced Book stores anywhere where I live locally... I do know of their website, if its the same company... Your example may be just a regional thing...
BTW, amusingly, and also anecdotal, the online version of Half-Priced Books, has more copies of KQ6 than they have of KQ8... That is to say, they have 3-4 copies of KQ6, and only a single copy of KQ8! They have 1-2 copies of KQ5.... 2-3 copies of KQ7.
Speaking of the 'used games market' and misconceptions...
http://www.cinemablend.com/games/Fro...mes-40612.html Speaking of a day and age, where even the most popular games end up going to the used game market in large amounts, and going the resell, with a possible glut... Generally speaking because most gamers aren't 'collectors', and are only interested in playing the latest and greatest games, and then getting a little cash back to buy the next latest and greatest new release....
On a related note, its not always the 'total amount' of used games found in a store that sells used products, but the price the used games are going for... The rarer or more popular generally cost more, than the common/mass produced or less popular games...This may all depend on the popularity of the game regionally. It also depends on the quality of the disk (is it scratched or not?), and other factors... So its all rather complicated, and very hard to follow to understand the reasoning why more copies show up in some places, and not others, why the price might be cheaper for one or the other, etc...
Many of those KQ5s for example on Amazon sell for less than 20 cents, and not more than $14 on the high end... Most of the KQ8 sell for over 60 cents, with most not getting higher than $20... KQ6 most sell over 50 cents, with most not getting higher than $20. KQ7 is selling for over $3.50 with most not getting much over $16.
Of course, 'pricing' depends on what local seller thinks they can get for the product, based on what they think the demand is...