Why Oracle won't kill openSolaris
From the "speculation of pre-mature termination" files:
Lots of chatter today about Oracle planning on killing off openSolaris, once it completes its acquisition of Sun.
In the true open source fashion openSolaris is the project that develops new technologies for Solaris. OpenSolaris is not just a standalone open source project, it is the Solaris 11 incubator. Sun officials most recently re-iterated that fact when openSolaris 2009.06 was released last month
Now there may be a question of priorities once Oracle takes over Sun which could limit the investment in Solaris overall. But don't forget that Oracle today supports multiple flavors of Unix, Linux and Windows.
Oracle supports a multi-OS strategy because that's what its customers want. I doubt very much that Oracle would want to alienate its own customers (that is, Oracle users who have been running Solaris for years).