A few reasons why Eliminates are expensive:
- A lot of players grind/level in Mire, a venue that doesn't drop Eliminate.
There's nothing to really elaborate here. More players in Mire, less possbility of Eliminates to drop so there's less to go around.
And fyi Crystal Pools, another popular leveling venue, also doesn't drop Eliminate. The only venues that give you experience at lv25 (for leveling fodder) and drop Eliminate are Boreal Woods, Harpy's Roost, Ghostlight Ruins, Kelp Beds, and Golem Workshop.
We've been aware of the coli undergoing a rewrite for some time now, and a lot of players are likely hoarding Eliminates in anticipation for the update. People think there's going to be major changes, even though the devs have stated in the last coli news update that they don't plan on changing the current stats except to address agility.
That said, the changes to agility might be enough that it opens up different kinds of builds, and there are a number of theorycrafters who would want to test new builds out so they're probably stocking up on Eliminates as well.
- Week-long open registration periods every month.
FR is getting a steady stream of new players every month and those new players often want their own lv25 dragons to fight in the coli. While the coli is not essential anymore for grinding festival currency thanks to the release of Balwin and brewing currency, the coli is still really beneficial even for a casual player.
I haven't been tracking the price on Eliminate for very long, but iirc before Welcome Weeks began in Oct 2016 (which coincidentally was when news of the coli revamp was last given), the price on Eliminate was around 120-150kT early last year. By June they had climbed to around 200kT, and that's probably because FR was having more frequent registration windows. And then Welcome Weeks started.
While some people say that the Eliminate drop rates were nerfed, I'm more inclined to believe it has more to do with all the new players coming in over the past year/year and a half driving up demand.
So lots of new players coming in, limited Eliminate supply available, and most players level in a venue that doesn't drop Eliminates. Thus supply stays limited and the price of Eliminates continues to rise.