Speculation here based on some other circles I've been in with other animals and such....I haven't looked into scaleless myself as it just feels like more work than I want for myself.
They may be keeping the supers/scaleless for their own projects. Remember they are still fairly new as far as morphs go so breeders may be selling most scaleless snakes to other breeders they're close to so they can promote outcrossing and new blood into the lines. I haven't tried breeding them myself, but the genes may also not work as easily as we make it seem. It took a VERY long time for the first Albino blizzard leopard geckos to hatch. That's with multiple breeders working towards it. I even tried breeding albino het blizzard to blizzard het albino and it just didn't work out once in 3 years.
The other thing to consider also is that they aren't the most resilient snakes either. They can dehydrate easily or have shedding problems. There may not be as many breeders wanting to promote breeding the super form like how the silkback beardies are discouraged by some breeders.