As a holly owner I second the prize owner's (The_Bucket) statement
The reason the value of hollies is so high is because (if you look at the data sheet in my sig) there is somewhere around only 78 CB hollies in existence, and somewhere in the realm of 840 CB prize dragons in existence. The number of hollies is probably higher than that, but any beyond that most likely have little to no progeny, and thus are inconsequential in a debate about trade value.
However, that doesn't consider activity. Only about 41 CB hollies are still actively breeding at Christmas times, with clutches normally averaging around 3.2 eggs. By my calculations and findings there are 728 2nd gen hollies in existence, which, if you count both CB hollies + 2nd gen hollies in existence, that's still less than the total amount of prize dragons.
If you assume even a quarter of CB prize dragons are actively breeding (210) once a week, and they breed true let's say 1 in 6 attempts (I get this estimate from Bucket), then they would have roughly 8 to 9 prizes in a year. So let's assume 8 prizes are laid per theoretically active prize (210). In that case 1,680 prizes would have come into existence within a year.
Last year 124 2G holly eggs were laid.
If we hold that calculation to represent how many 2g prizes are equivalent to a 2g holly, one would need to promise roughly 13~14 2G prizes per 2G holly.
Now, if you ask me if I am traded that much each year, I'll tell you heck no. Last year I traded my holly egg for a CB almandine, two CB golds, and a copper or two. To be honest, I don't find anything truly as valuable as a 2g holly unless it's a 2g holly. I also don't think I'd believe someone trying to trade me 13+ 2G prizes
Holly owners get the short end of the stick when it comes to trades, because no one really wants to give them what they're really worth (unless they're another holly owner doing a bloodswap but that's beside the point). And this isn't to say the people who trade for them are bad, or purposefully underpaying, but because there are so few holly owners, and until I created my sheet I don't think anyone really knew how few and far between we are.
However, we holly owners see the happiness it brings to people and I know a handful of 2G holly owners who regularly gift their hollies or donate them to competitions or drop them on people's heads. I love the reactions from people who grab my eggs in the AP and seeing how happy people get when they receive one or grab one or win one makes the unfair trades worth it.
On the other side, we also tend to get pestered or asked for lots and lots of trades, even out of season. It's hard to talk to someone without our hollies coming up in conversation, and that sometimes causes us to withdraw.
I'm going to stop blathering now because I'm already neck deep in this post and I've gone on waaay longer than I should have If you have any more questions on the state of hollies, please feel free to PM me or ask here.