Comment by nyrikki

IMHO the ORM was an unfortunate choice for trying to develop a generalization about abstractions.

SQL's declarative model has an impedance mismatch with imperative programming, ORMs attempt to deal with that mismatch.

SQL hides complexity but Codd's goals when developing the relational model was to allow non programmers to access data.

The design decisions and tradeoff analysis was massively different than just an abstraction targeting developers.

There are many different persistence models that have vastly different tradeoffs, costs and benefits.

Balancing integration and disintegration drivers are complex and can impact optimization in many ways.