Well, I don't necessarily think that's purely a Hybrid snake problem? I think that has a lot more to do with the fact that is was widely believed by many that the different species of House Snakes were only various locales/morphs to begin with and then by the time the fact that they were strictly different species there were already too many crossbreeds on the market. All in all, that seems more like a breeder problem than a hybrid problem in my opinion...
However, there is an increasing amount of interest from breeders who value pure lines in regards to House Snakes so I'm sure in a few more years, we'll have more purebred specimens to choose from.