Austerity is why Councils can't dump Oracle...
Oracle has always been a textbook exercise in "Embrace, Extend, Extinguish", far more egregious than anything MSFT ever tried with JScript. You can run compliant (i.e. portable) SQL89, 92 and 99 on Oracle, but the entire ecosystem tries to push you into using proprietary PL/SQL extensions and locking yourself into the Oracle platform.
There are various Oracle emulation layers for other RDBMS (EnterpriseDB variant of PostgreSQL, for example), but then you run into the other insidious aspect of Oracle: sales parasites deeply entrenched in the 'C' suite peddling horrific warnings about the risks of straying from the one true path that would make the 13th century Vatican blush ...and then there's the straightforward bribery.
I've been encountering Oracle off and on since Oracle 8 ('90s) when they tried to convince me to port a major public sector system over from Ultrix/Ingres and have never once encountered a scenario where Oracle was the best tool for the job when considered holistically (meaning factoring the cost of licenses and audit compliance). It doesn't matter if Oracle is twice as fast (which it almost never is) if you can double the capacity of your cluster by not financing the local Oracle rep's next Breitling watch.