Let's be blunt: Oracle is, at this point, almost completely dispensable.
The reason that Postgres is being maintained and Oracle is not, is being Postgres is what is actually being used to develop new packages and then deliver those packages.
Those people still running on Oracle have already committed to OpenACS and are in maintenance mode with their code; so they would have to backport or otherwise modify code in any case.
ALL of the growth going forward, as the OpenACS and .LRN communities grow, will be on Postgres.
While I was at EduCause, not one IT person I spoke to was even interested in Oracle as a base for a web-facing application. While the brochure on .LRN mention both Postgres and Oracle support, the questions were more about features-and-benefits and support issues.
This is not an isolated, OpenACS-only situation, either. Sakai, Moodle etc. use different databases and only incidentally if at all, support Oracle (e.g. Sakai supports it because they have a JDBC-based layer and support for Oracle 10g and MySQL are what have been written so far).
The days of Oracle support are numbered, unless and until the folks actually using Oracle step up and do it themselves, just as the Postgres users have done.
