That's part of the failure in developer mindshare: leveraging SMT for games in 2005 was difficult enough, heterogeneous multi-ISA hardware, a ring bus, and the peculiarities of the SPEs made the PS3 not really a consideration. Things might have been different if sony had provided ready-made more or less plug and play SPE applications you could use with just a little tuning for your circumstance (e.g. a physics engine or something) but as far as I know that wasn't the case. I've never heard Sony being praised for its SDKs, while the 360 had straight up directx (with more hardware access).