I’m not sure why object oriented databases were a thing other than people liked to write OOP. The fact there is such a huge impedance between the structured data and management code seems to be a huge demonstration of cognitive dissonance in favour of OOP.
Part of it is that DBA's got a bad reputation for bottlenecking projects for many different reasons. Some of it legitimate, as they wanted to make sure schema design was consistent, properly normalized, and followed org standards; but some DBA's were control-hungry.
Therefore, developers tried to minimize their need to go through a DBA by doing more data-ish things inside the application itself. That's more of a staff management problem than a technology problem, but OOP had the "fad cred" of the time and often bowled over DBA's. The pendulum has started to swing the other way as reinventing the database & querying in applications has proved messy.
