There are several reasons:
1. People were burned by the first one
2. Is a short game, around 10-12 hours
3. Lack of local multiplayer
4. Lack of any online multiplayer
5. A lot of people pirated the game (more than 800k according to a torrent website)
6. Very little advertisement
7. Awful launch date, same month as Battlefield: Bad Company 2, God of War 3 and Final Fantasy XIII