I think of corals a bit like footy cards, buttons, coins, fossils or anything else that people collect. If you can get it at every LFS or OLFS going, then of course it's not going to be as valuable. If you see a piece you like* that is not available anywhere else, is rare, or is just not seen very often, then it is worth more.
*important because rare doesn't always mean valuable - a one of a kind poo brown scoly is going to be worth fuck all.
Some of the new premium stock available at the likes of UCA, Elite Corals, and others, I haven't seen before (and I look closely, every day pretty much for the last couple of years), and they are stunning. To me that means the price can be whatever the seller wants it to be. If it's too high, people won't buy. If it's high but someone really wants the piece, and they pay it, then good on the seller.
For example ... zoas. Who can point me at a seller, right now, who will sell me a Soprano? A Purple Hornet? Or a My Clementine? Or something equally as stunning and unusual? I know they are out there ... most people that own them wouldn't be interested in the $$s to sell them. So if something like this comes up for sale, I say it is fair game. Someone put a true Soprano zoanthid up for sale and I would probably pay whatever they wanted for it ... and be happy. If I would pay $50 for a polyp, why would the owner charge less, just to make it 'fair'?
Same goes for UCA - sure they have some items that, as someone who does look at these things closely, I believe are way overpriced (some of the morphs in particular). If nobody sees the value, then they will go unsold. Some of the pieces are awesome value - stuff you don't see at the LFS or on Facebook sales. 90% of the shit sold on Facebook is just that, shit - particularly a lot of the specials and auctions.
Anyway, bee out of bonnet ...