Rumour has it the same holds for some other types of data as well but I lack immediate experience in other areas.
With Oracle you also have a rather robust, exhaustive documentation of error messages and even obscure stuff is likely to be figured out in some forum thread by someone and an indian guy. Postgres isn't exactly bad in this area but you can run into things where you need to go deep in debugging yourself and figure out minutiae of your specific version.
Containers also remove most of the issues with running several instances in development and CI environments.
I still don't recommend anyone to pick Oracle for greenfield stuff, instead you should work around shortcomings in other database engines, but for a large organisation with certain demands that already has buyin it makes sense.
This is just on top of the general technical inferiority (eg there are no transactional schema changes, so you don't get the safe go/no-go in those when applying those as part of app deploys with a migration tool)
You need to decide if and how to perform a rollback, similar to how you would define a down() procedure in migration files. A schema change might imply changes to data, and in that case you might turn off client writes, copy the table, change it, validate, do rename dance, turn on client writes again. If it doesn't it might be much cheaper to operate on a single copy. How does Postgres decide on such strategies automatically?
If your "db cluster" is split into containers on one VM as you would do in any other cloud (because VMs are expensive), then you would have the same problem.
> encouraging monolith DB consolidation
Does it? I don't think so. I've worked with Oracle's stuff and the only real difference between Oracle Cloud and other clouds is that Oracle cloud is more expensive overall. There's nothing stopping you from running virtual machines and kubernetes in the same way you'd run it in any other cloud.
As Oracle is so expensive it skews the architecture decisions towards multiple apps accessing the same DB.