I would argue that the failure extended to the user-perceptible performance deficit vs the XB360 despite arguably more capable hardware. Released games didn't perform better on the PS3 even if they technically could.
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).
