I don't have a lot of the experience, but from what I've read, one of the things that makes the ball pythons so much more available is not only their easy-going temperament (even for wild caughts), but their readiness to breed in captivity. Importing is such an "iffy" business. Animals may not adapt well to captivity. The stress of capture and shipping can cause a high mortality rate. Parasites can quickly spread from one animal to another in the shipping process. Animals may not feed in captivity, etc etc etc.
For many of us in buying our first snake, we look at the cost of a captive bred BP, starting around $25 to $35 for a normal. It's healthy, high likelihood of being parasite and disease free. It's friendly, having been around people all it's life on top of having an even temperament. It'll stay a manageable size, and in many cases is already acclimated to eating F/T food. People with lots of experience with them are plentiful.
Other species aren't as readily available CB. If we buy an import, we either pay a higher price if it's already been vet-checked for disease or parasites. It may be more finicky about diet. It may be more skittish around people. Some species get MUCH bigger, requiring their own special care requirements.
Hopefully, some people with much more knowledge and experience will chime in some opinions, too. I just hate seeing a question that seems to be overlooked or ignored.
