While those dimensions are small for a CNC router, they are large for a 3D printer. The inexpensive machines you may have heard about tend to be much smaller. Scaling them up increases the expense of the machine considerably, while making bigger parts takes a lot longer, all other things being equal. Unlike routers, printers need to move quite fast but don't need to be nearly as rigid. Printing in ABS requires a heated bed, or the parts warp off the build plate as they cool.