Most developers using these kinds of tools these days are actually building their own database management systems, just outsourcing the persistence to another DMBS, so there isn't a strong imperative to think about good design so long as it successfully satisfies the persistence need.
Whether we actually should be building DMBSes on top of DMBSes is questionable, but is the current state of affairs regardless.
A previous employer thought that sql databases didn’t understand graphs. So they made their own system for serializing/deserializing graphs of objects into Postgres
. They never used queries and instead had their own in-memory operators for traversing the graph, had to solve problems like deleting an entry and removing all references, partial graph updates.
Whether we actually should be building DMBSes on top of DMBSes is questionable, but is the current state of affairs regardless.