It didn't sell because they didn't advertise it. I've never heard of it, let alone have any interest in it...
Whilst the rules regarding WiiWare are silly, the 'excuse' of 3rd parties not selling is wafer-thin. For example, look at Epic Mickey, Goldeneye and Monster Hunter Tri. 3 discrete devs, who all made the effort to produce a AAA 3rd-party Wii exclusive, all of whom received sales of over 2,000,000 for trying.
To put it simply, don't put in the money and effort to let people know it exsists, you don't reap rewards, and vice-versa. They have, sadly, no-one to blame but themselves.