A few things to Add about Solaris profitability

A key difference between Redhat and Solaris is: DTrace. Dtrace allows support engineers to resolve customer production issues a lot faster than Redhat, there is no need to send the customer debug kernels... This results in better customer satisfaction and reduced servicing costs for Sun.

Another difference is ZFS that architecturally is also more reliable by architecture with end to end checksums and the fact that ZFS is always consistent on disk and thus not requiring FS repairs after a system crash. ZFS clone and snapshot support allows for safe upgrades that can be rolled back safely... This also reduces Sun's support costs.

My point is that at least theoretically Solaris support business can be more profitable then the Linux business...

Solaris still has some catching up to do with the user interface in some areas, but still manages to out-innovate Linux with features like Time Slider ...

The future for sun and its shareholders is not that bleak, if redhat can have a market valuation of 3.5B $ with 0.5B in revenue, Sun with 13B of revenue can certainly do better than its current 5B valuation..