I've been reading various posts on the state of the vintage bicycle market with a lot of interest. Mike Kone and I had a little colloque about it a couple days ago.
It strikes me that the market for old bikes has always had a large random-factor in it, especially on ebay, as you never know who's looking from week to week. all it takes is a couple of avid collectors who weren't paying attention in a given week, and something goes cheap. So, it would be mistake to draw many general conclusions from only a few data-points.
Private sales of prime specimens are still quite solid, from what I've heard, although, again, the market is so small, relatively, that this too can be a matter of who's looking and who has a little extra cash at any given time.
I also agree completely with Greg Parker's point that, right now, the US consumer is, in general, feeling distinctly pinched, and is likely pulling in the horns for the time being.
All this said, I agree the market is changing. I think, on the one hand, certain buyers are less discriminating, in the sense that they're going for the bling rather than the substance, or for the paint rather than the craftsmanship, when it comes to 80s bikes.
On the other hand, and in direct contravention of that notion, other buyers are getting much *more* discriminating. For various reasons. You can list those reasons as well as I can. But this is the sort of thing you see in a maturing market for rarities (although old bikes are pretty modest in both price and status in the world of true rarities). People get much more discriminating about what they'll pay the big bucks for.
Put a 1970 Masi GC with the first graphics package, in clean, original-from-the-shop condition out there, in a good color and a good size, and I daresay you'd see some action. I don't think interest has waned for that sort of thing. I could be wrong...but that particular bike is uncommon enough that it might be awhile before I'm proved wrong, one way or the other.
Or, put a nice, original colnago pantografata from the early 70s on ebay, again, fully original (or plausibly so, anyway), with a good paint-color and good size, and, again, I doubt it would go for peanuts.
Or a 70s cinelli Super corsa in silver and chrome, in good, clean, original condition in a good size...that bike will go north of 3K pretty readily even now, I think.
And a good size is 54-57cm c-t. Anything smaller, or larger will have a much smaller universe of potential buyers. I'd be reluctant to draw conclusions from sales of bikes sized outside that range.
It's becoming in bikes as it is in every collectible field: only the choicest bits command the big bucks.
This strikes me as an excellent thing, because now many very nice old bikes can be had for a song much more easily, meaning nearly anyone can develop a nice stable for less than the price of a cheap used car. Seems like a good thing to me.