Sorry to echo a lot of what's been said, but as one of the "younger" guys who's into postwar I figured I'd chime in. Some of my perspective has changed because I'm 25, have been out of college a few years, and have some disposable income. So even if the prices haven't gone down, $100 doesn't seem as much as it did when I was a teenager and was saving my newspaper money (talk about getting out of a dying business at the right time) for a car and college.
Anyway, I've been told the rise in prices in the 80s/90s was the baby boomers wanting to buy what they couldn't have as a kid. Now some are dying or selling out so the market is being, not quite flooded, but seeing some large collections for sale.
When I was a teenager and budding engineer I was determined to get my money's worth so I bought old trains and accessories that needed some TLC and taught myself how to fix them up. I still do that, but I have been able to get more and more deals on items that need less work. So as was said above, there'll always be a good market for clean operational postwar, so I'd buy lots, fix it all up, keep a few items and sell the rest. And one could observe that with the interest boosted by stuff like the polar express, etc, the clean operational stuff is still selling well.
Granted even if "the prices" are going down, people are still asking big bucks. A lot of that from people outside the hobby comes from the countless pawn, picking, and auction shows, everyone thinks what they have is gold.
The more and more I think about this, the more I think of some other factor and I change my opinion.
When I sell something I look at what it's been sold for recently (if I see one more article about how beanie babies are still worth money because somebody has them listed for thousands on ebay....). You can ask whatever you want, but it's no guide. To bring it back around, I think I had the 1998 and 2000 editions of greenbergs, but I haven't bought one since. There are a couple good websites I trust for information on variations and history of postwar pieces, so I get my info there.
