There is definitely merit to the notion of using persistent memory to address state management. But neither this (nor "noSQL") in any way addresses the other f

There is definitely merit to the notion of using persistent memory to address state management. But neither this (nor "noSQL") in any way addresses the other fundamental utility of a database: querying for data. The need for a (form of) structured querying language (such as SQL) remains regardless of how state is managed. If you are not convinced, simply pretend that your heap is in fact a persistent store (and don't worry about process life cycle) and think through the problem of writing code to extract sub-sets of your object graphs. By the time you are finished with your enhanced collection/graph interface you have reinvented a form of query api. Its not just about state.