I see what you're saying. For example - for me personally, I am mostly interested in RPGs, so the "average" price of games I am interested in is probably much much higher.
But just for the hell of it, I took out all the games listed by VGPC with a category of "sports, baseball, basketball, wrestling" etc., and was left with 572 games.
Of those 572, the average price was $13.49, with 490 games less than $20, 388 games less than $10, and 263 games less than $5.
(Disclaimer: The "Average Price" probably isn't a good indicator anyway --- the Median Price of the above list is only $5.50. With such a large number of items with a wide range of prices, the average isn't really that interesting. The median is much more meaningful).
I'm not really trying to prove much here I suppose, hehe. It really just boils down to supply and demand, and the free market.
There are tons of factors that affect both sides of the market equilibrium. Rarity, popularity, "nostalgia factor," potential for future profit - these are just a few factors. And while I wish people would actually buy games for enjoyment, I think what we have now, that didn't really exist before, is a huge market for speculation - people buying games to resell later, or buying with the hopes that the value will increase over time. The internet has made it SO easy to research prices, easily access the items, etc., that it wasn't really something people did as much back in the day.
Unfortunately, I have no more right to buy a game on the open market, than someone who wants to snatch up 50 copies of a rare game to hold on to them and sell slowly to increase the price and make a profit. I would agree with most people here that it sucks that there are so many people doing that. With certain games being so rare, it is actually possible for 1 person, or a very small group of people, to influence the entire market for a particular product. It is much like a diamond cartel holding diamonds and selling them in small quantities to keep prices high.
There isn't really a big point here - I'm just letting my brain flow - I think ultimately it just boils down to one of those "deal with it" or "life isn't fair" scenarios, because there will always be people who in our eyes are into gaming for the wrong reasons, and people who screw things up for everyone else. But in that sense, I don't blame the OP for 'venting' as he mentioned, because it is disappointing sometimes.