I don't see it ending any time soon. IBM currently holds the largest market share for UNIX servers and Oracle would rather see their DB on those rather than DB2. As long as there is still a good market share in the high end server market, then Oracle will continue to provide it just as they do for HP and did for Sun before buying them.

Why is it people assume you have to run Linux on Power hardware for Oracle? AIX fully supports Oracle RDBMS solutions, including combining them high availability products such as HACMP. You buy Power hardware for the reliability and performance in mid-large scale computing. Someone that can afford to put Oracle on that kind of hardware usually runs AIX vs Linux.