This is true, but misleadingly not the whole truth. On prem RDBMS is dying and its niche shrinking (at least in this part of the cycle)... having said that, Oracle cloud offerings are doing very well.
Amazon made a herculean effort, and made some headlines when they migrated most of the business off Oracle last year. That's wonderful, for Amazon. Most of Oracle's enterprise customers are not Amazon.
> I'd also prefer a galera or an innodb cluster
The thing is.. Oracle sells so much more than just an DB engine, and people are buying. Oracle RDBMS is not an inferior product to open source competitors, in most ways superior, and yet, it is really just a proverbial loss leader.
Are Oracle cloud offerings actually doing well? What evidence is there of this?
It is also in a lots of extremely critical ways inferior. The huge complexity, the huge footprint, the humongous prices are enough to justify staying far away from it.
When you have thousands of engineers, "complexity" is very subjective.
It is not. And I know of several major banks leaving oracle "en masse" because of licensing nightmare. The major decision makers are now endangered by their choice of oracle as a database to consider. Oracle in a new project is now a firm NO.
Regarding HA, active/passive and failover is enough for 99% of the use cases. For the rest you'd need citus or patroni, but it's totally manageable. I'd be quite dismissive of an architect who suggests oracle if there are no extreme availability requirements. I'd also prefer a galera or an innodb cluster for active/active architectures.
Let's face it: oracle database is dying an its niche is shrinking.