I know what you're talking about. It's so weird you posted this last night- I was literally talking to my husband about the 2010 shift about an hour before I saw this post.
Before 2010, I'd say the typical going price for a grail was $300 or so. Of course, there were SOME pins going for more, but not a lot! And grails took TIME to become grails- they usually weren't grails right off the bat. Even the pins that were popular right away still went through periods were they were $50, $75, $100, etc., before they went super high.
Around 2009/2010, it seemed like pin trading was going to die. A lot of old time pin traders left the hobby, Dizpins shut down, Pinpics got sold, ds.com stopped releasing the "high-end" pins...actually, in general, pin releases were pretty sad around then! Then, something happened, and a new wave of traders/collectors/resellers came in. I know DSSH carried us for a while, as far as nice, low edition pins. I guess the WDI wave started with D23 Expo and the pop-up stores?
But yeah, that "it's a grail right away" mentality really changed things. Nice pin + a lot of people who want them= crazy demand! It's been tough to get things to trade for some of these pins!
I think...for prices to come down some, one of a few things would have to happen.
1.) More access to/types of low edition pins (like ds.com coming back)
2.) A lot of people leaving the hobby (demand shrinking)
3.) Complete hobby collapse (like Beabie Babies, although those are starting to come back)
4.) Apocalypse
WDI pins are an interesting study. In some cases, you'd expect some of the prices to go down eventually, due to the type of show/character not being as popular anymore. Like someone mentioned above, we've seen some characters flex in popularity, like Tinker Bell and Jessica. But so far, most of the WDI pins in the "new era" (not the older WDI pins) are keeping or increasing their value. I wonder at what point the market will get flooded enough that some older sets lose their appeal...
I don't know that I added anything to the conversation, but it was wild to me because you posted JUST as I was thinking about this!