ive always wondered about this and if it was because the cost of dubbing a show is higher than any profit the licensor could make
but then stuff like the monogatari series goes without a dub even though im positive it'd sell well.
a big reason too i guess is aniplex licensing it.
but yeah, idk if this still applies, but if aniplex or sentai license a show, unless it's notably popular, it won't get a dub.
afaik righstuf doesn't really dub shows i think, sunrise probably just got them as a distributor.