I don't think the "slow burn" philosophy applies to all titles. A lot of the games that I hear associated with that phenomenon are games that had big brand recognition to start off with (Call of Duty 4 on DS, for example), or were re-marketed in some way. If Excitebots isn't re-marketed down the line, it's doing to die a quick death.
13,000 copies in two weeks is awful no matter which way you cut it. It clearly shows that the market that should have known about the game, and would have bought it, didn't even know about it. Excitebots is a quirky title, and if people aren't shown its strengths they won't know anything about it. Heck, they probably wouldn't even know it's a racing game.