I think because if anyone takes one good look at what Cubicle charges for cubes, and what they actually cost from sites like Zcube, it seems like a very easy way to make money. The problem ends up being that they are run poorly and don't know how to advertise.
Being in the US, a pretty rural area doesn't have any cubing stores. I wish it did though, it'd be so much better to go there and see and feel cubes in person before buying.