And, just like every Unix workstation vendor of the 1990s, they got hit with a perfect storm. They had their hardware being disrupted by x86 really coming into its own as a viable option for higher-end computing at the exact same time that Linux was becoming a serious option for the operating system.
"Literally something that should not exist" is the perfect way of putting it. In 1990, lots of people needed boutique workstation vendors. In 2000, nobody did.