1. Marketing - Corn snakes are marketed by breaders like crazy and many consider them the perfect first snake. There is no rational arguement for why a corn is better then many common rats, kings or milks. The care is the same and they are about the same size and all are easy to care for and many milks are simply beautiful beyound words. Corns are most popular because they are marketed like crazy and ball pythons are a very close second. Ask what is the perfect first snake in most forums and 80-95% will say a corn snake or ball the sad part is 70% or more of the people saying that won't really have a modest clue as to why, the marketing simply created the preception to the point that it is now simply that "everyone says so".

2. Ease of Breeding - Viper boas will probally never be very popular unless the secret sauce to breed them is discovered. They are docile once tamed, small and pretty but they will never make a big splash unless a breeding formula is unlocked. Marketing is always first and the top breeders are not about to market a snake unless they can consistantly produce it for a PROFIT.

3. Tempement - Black Racers and Coachwhips are beautiful but both bite a lot. People do not like pets that bite them, so neither is likely to make a big splash anytime soon.

4. Size - While a 10 foot taiwan beauty is nothing like a 8 foot boa it is still one big snake. I love mine and I know you love your blues but many are (rightfully so) intimided by them. They move fast and take some experience to handle safely if nothing else to handle safely for the snake itself. Albino Burms are now like 200 but Albino Balls are four figures because it is easy to keep a ball python. The future of Retic and Burm morphs will be in dwarfs, trust me this will go right back to item one, marketing.

5. Information - To create a market you need awareness and acceptance. Google Rufus Beak Snake you won't find much info yet. I predict they are the next big colubrid boom to occur but not yet because there is no awareness on them. The good news here is this one factor can CREATE a market for the entreprenuer. If you want Blue Beauties to become envouge, the be an apostle for them. Create tons of web pages about them, get info from many keepers and create discussion groups around them. People often fear keeping a snake they can't get a lot of info on even when the truth is their care is just the same as a corn or king with a slightly larger viv.

Probably more then you wanted to know but as a business person this is the way I see the issue. Hope that helps,