Summary of of how the Big Hitters played.
This is how I saw it on the ground:
Microsoft - did have a directly-competing x86 OS (Windows), so took full advantage of the affair to FUD Linux; definitely slipped SCO some cash with "evil" intent; and provided their sales with FUD material to attack Linux (I sat through one from an MS partner). TBH, what else did you expect?
SUN - took advantage of the affair to FUD Linux in an attempt to defend their proprietary UNIX; paid SCO up front for a license early on when it was already clear the SCO threat was hot air; and sent out their salesmen with a FUD packet to attack Linux with, despite prior claims of "penguin love" (I sat through one specific SCO-Linux FUD session from a SUN reseller). Upset some old timers that though SUN should have been defending Linux more, alienated the Linux community.
IBM - took it on the nose and sent their flying-monkeys/lawyers into battle (partially with the intent of defending their profit stream from Linux on mainframe), despite having their own proprietary UNIX and large MS-on-IBM revenue streams; and provided their partners with anti-FUD material (I had a briefing directly from IBM). Won the respect of the Linux community.
hp - despite having their own proprietary UNIX revenues to protect, and despite being the number one vendor for SCO UNIX servers, hp told SCO were to go when asked to buy a license; despite being the number one MS server vendor, did not issue a Linux FUD pack for their MS salesbods, but did supply material to resellers to de-FUD the SCO issue in Linux sales; issued a public statement saying they would indemnify hp customers using Linux, nullifying SCO's legal threat; and doubled down on their relationship with Linux vendors (I sat through joint hp-RedHat and hp-SuSE briefings on the matter). Surprisingly, did not make as much publicity noise over their rejection of the SCO case as IBM, but then that is hp's "cold-dead-fish" marketing to a T.