I fill a bit of an odd niche somewhere between a technical assistant and a nurse, yes - sorry, normally I explain myself a bit better! I always forget who I've told what (and when!)
So, to my understanding (which I confirmed with the tech/nurse on duty), prescription parasite medications are much stronger and tend to cover a broader spectrum of potential parasites in one treatment. Over the counter meds purchased in pet stores tend to be less effective/potent and/or only target one species of parasite, which is totally fine if you're 100% sure what you're dealing with.
I absolutely agree that deworming is something that can be done at home, at least with dogs, cats, and some bird species (I.e. poultry, waterfowl; very little is actually branded for psittacines!). The problem with creating medications for reptiles is that you need to take into account that every single species would require a slightly different concentration, and a medication would be highly unlikely to be both safe and effective in every case if a "multispecies" approach was taken. The difference between a box turtle and a ball python is as large as the gap between a cat and a dog! It gets complicated very quickly, and I suppose the market isn't quite large enough to support the research. In addition, the effective drugs and protocol for treating a protozoan such as coccidia are way different than, say, pinworms. While it's possible to perform a fecal float at home with a little know how, most people aren't willing to go to that length. This makes it very difficult to market an already niche medication, especially when you consider the amount of research (and $) it would taketo produce it in the first place.
I can honestly say that exotics medicine is very much still in its infancy, and we're forced to use drugs off label and essentially make educated guesses regarding the dosages. There's very little set in stone, and vets have forums of their own to go and compare notes! Deworming can be a bit of a hot topic with exotics vets, it seems. Or at least with mine! I have one vet that just shrugs and says "they pretty much all have parasites and do fine" (old school vet), and the other that believes it's better to identify and get rid of them before they become a problem (more progressive vet).
I think I covered all of my bases, but please let me know if you have any other questions! I'm coming off of a graveyard shift, so I apologize if my thoughts are at all scrambled.
~Amanda