Haha, as a mathematician, the notion that math sculptures are the killer app to bring 3d printing to the masses is pretty suspect.
Ultimately, these printers are one tool in an arsenal of tools for making things; they don't stand alone. There article gets it right that these are more likely to be tools for hobbyists and professionals who need lots of physical prototypes and (maybe) schools. These aren't trivial markets at all, but also aren't all of the people in the world, either.
(Or you could just have Shapeways do the printing.)