SGI didn't commit suicide. The market just ate them.
Around 1999 the Octane were about 50K, at the time NT machines (think Ingergraph) appeared that were, for many, many purposes, just as capable. They were 10K.
In addition the MIPS chip was considerably worse than a dual proc x86 machine of the same vintage. I was working at a company where there was a C++ API. Compilation time on the SGI was 3 hours. It was 10 minutes on the Intergraph.
When cards like the Nvidia Quadro and FireGL cards came they were better than SGI machines and cost a few thousand dollars.
SGI's model of a proprietary in house system just stopped working as x86 and graphics cards just got better and better.
Even the high end Onyx graphics setups became obsolete a few years later when clusters of PCs started to kick in.
SGI's engineers have gone to places like ATI & Nvidia. While it's sad to see that the company is pretty much worth nothing, it's not the end of the world. SGI did great stuff but their time has passed.