Quoted from blownfuse:
I think it's called supply economics. I've been a collector/route operator/buyer/seller since 1973, I've never seen prices go down as more collectors joined the hunt to build a collection. The prices were flat at times but they've always climbed up and never retreated, even on the older games that have been kept in nice condition. Heck, even the remakes will go up in price. Sorry, I just don't see a price drop happening unless we have a full collapse of the economy. Then we have more important things to worry about than pinball prices.
I agree. B/W titles in great condition are unlikely to fall much. Even with the recent real estate implosion, the pinball market was very healthy. Most Stern titles are safe as well, with the minor exception of re-runs that have a short term impact on some titles.