This is what I see holding some applications back.
The relational model is flexible and sufficient for many needs but the ACID model is responsible for much of the complexity in some more recent solutions.
While only usable for one-to-many relationships, the hierarchical model would significantly help in some of the common areas like financial transactions.
Think IBM IMS fastpath, and the related channel model.
But it seems every neo paradime either initially hampers itself, or grows to be constrained by Codd's normalization rules, which result in transitive closure a the cost of independence.
As we have examples like Ceph's radios, Kafka etc...if you view the hierarchical file path model as being intrinsic to that parent child relationship we could be distributed.
Perhaps materialized views could be leveraged to allow for SQL queries without turning the fast path into a distributed monolith.
SQL is a multi tool, and sometimes you just need to use a specific tool.