My abstraction can beat up your abstraction
Relational is about much more than JUST "storage". That is what OO'ers don't get. They use it JUST for storage, but then end up reinventing all the other stuff in their OO app anyhow. They have to reinvent it because OO does not provide enough power out-of-the-box. To add it requires reinventing a (navigational) database. Relational provides a fairly standardized way to manage state and noun attributes that OO lacks. Everybody ends up doing it so differently. Plus, OO often hard-wires access paths into the design.
If I wanted to be able to easily swap database engines, then I could just use lowest-common-denominator SQL. But why don't I do this? because I want to use the rest of the DB features also. BTW, SQL is an interface, not an implementation. Ponder that. The only way OO systems get out of vendor lock is to have a translation layer. There is no reason an equally-powerful (and maybe equally flawed) intermediate query language could not be built for procedural. The fact that it does not exist likely means the need for it is not as great as OO'ers claim. Plus, the OO frameworks tend to be language-locked. Thus the choice is DB vendor lock or language lock so far at this stage in the swap wars. Pick your poison.
If you can clearly demonstrate that OO is higher abstraction without fuzzy zen talk, be my guest.
