If you bought WOZ as an investment, you're doing it wrong.
This isn't a run of 300 games. There will probably be thousands of WOZ's out there. I can't see the value of a LE run of 1000 games going up dramatically. Not when the pinball market isn't really growing as much as enthusiasts are just entering a phase in their life where they have a little more disposable income. At least that's my theory.
The fact of the matter is, the pinball community is really small. One thing that's contributed to prices rising is the Internet, which allows people to buy and sell machines from across the globe. This has allowed buyers to find games they wouldn't normally find and created a little more competitive market, but it's mostly a small market of people buying and selling amongst themselves. Prices are also going up because more and more enthusiasts are taking control of the available inventory of machines that have historically been spread across a variety of warehouses, barns and laypeoples' houses (these great deals are drying up for obvious reasons). There's a finite amount of games out there and they're slowly being found and put into the market.
Again, this market is small.. .how small? Well a few extremely aggressive enthusiasts can control large regions. Some regions of the country have extremely aggressive buyers who monitor CL posts by the hour. Those guys will travel a thousand miles to pick up a good deal. They have warehouses of games. There are "flippers" now in the market who are stockpiling games. And this also drives up prices. It used to be people would buy games for their own use, now they get extra games for trade bait, and some people have warehouses of games they sit on because they can. All this drives up prices, and makes good game deals harder to find.