Not trend setting, that's hair styles and clothing options. It's market value. If it really bugs you, perhaps snake selling isn't for you. There is an entire site whose main focus is this very topic, you may want to check them boys out.
When I first started breeding calkings heavily in the early 90s I could get 150.00 for my more unusual ones. Now, I'm lucky if I can get 20.00 to 40.00 for them. If I didn't like them so much I wouldn't work with them at all. It's the nature of the business. Can't blame the other guy, that's free enterprise at work.
I often wonder why hobbyist breeders get so bent by this. After all, NONE of them breed for the money. Do they?