In my experience Sun has been a leader in providing outstanding value in the Unix Server market with a combination of quality hardware and the Solaris OS... But they've always been seen as a more leading edge provider and therefore were pulled along in the wake of aggressive businesses like financial services.
I know... I remember back in the late 80's on Wall Street and the 90's in the web start up community, we couldn't buy the boxes fast enough. When those industries took a hit, Sun was pulled down with them like a swimmer wrapped in a boat anchor.
"...more important, the hardware represents a buy-in by customers that doesn't exist in the commodity world; you don't change vendors in the high-end Unix server world because another vendor is offering a better promotion..."
via forbes.com
Conservative customers perceive blood in the water and are voting with their dollars for the second tier Unix Server producers like IBM and HP. Too bad... Sun has given so much back in the form of quality software in the market. James Gosling has only half joked in the past that "Sun issues Hardware as a receipt for software"
This Forbes brief also highlights the severity of the matter