It's interesting how this trend died off so hard. I'm guessing what drove it was people buying into Sony's marketing hype (so powerful you can't export to Iraq!) and trying to get some halo hype, yourself. What killed it was the clusters being a hassle to manage and use, limited longevity, consoles moving to commodity hardware (hah! Xbox was already there), and OpenCL/CUDA and the rise of the GPU.
I don't think the trend really died. This helped show the power of dedicated vector processors, and happened to coincide with commodity video cards with the same sort of processors being more widely-available. There was a brief window where buying a whole PS2 just to get the vector processors was the most cost-effective solution, but the market quickly adjusted to fill that niche in a better way. This was a spike, and then they implemented the real thing.
