The proprietary-Unix sector will almost completely
collapse. Solaris looks like a safe bet to survive on high-end Sun
hardware, but most other players' proprietary Unixes will quickly
become legacy systems.
(In early 2000 SGI's IRIX was dead-ended by official Linux
adoption within SGI itself, and in mid-2000 SCO agreed to be acquired
by Caldera. It now looks probable that a number of Unix hardware
vendors will switch horses to Linux without much fuss, as SGI is
already well into the process of doing.)