[F_J_H]

That is somewhat of a concern, but less so now that they support web services. So, you would still need a basic oracle DB set up in order to run APEX, but you could just use OracleXE, which is a quite capable free version, and then connect to whatever you want.

Also, you see this argument a lot - "what if I want to switch databases"? I've seen more than my share of overly-complicated and highly non-performant code bases, "just in case we want to change our database at some point" (see the ORM messes out there.) Its a problem in theory, and in my experience, not in practice. Never in 25 years of IT work have I switched databases, so it's often a classic case of "prevention worse than the disease".

One case where this use to be an issue was for software vendors that used to sell applications requiring a database, and they had to be ready to work with whatever the customer had. In our day of cloud based apps, this is increasingly becoming less of an issue.

[ants_a]

"What if I want to switch" is a valid question if your business is at the mercy of a single vendor with a history of abusive business practices towards its customers.

While I may have a selection bias, I have seen quite a lot of companies migrating their applications, successfully. Most for exactly this reason. And many, perhaps even more, that would very much like to migrate if it was less disruptive.

[F_J_H]

Yep - agreed. It's "pick your poison". No matter what tech stack you select, migration away from it is a may be a consideration. (Whether it is a JavaScript framework, PHP to python, C++ to Go, or one DB engine to another.)

If being able to easily switch technology stacks is important to your business success, then you need to optimize for that. That's not the case for me.