There's some neat stuff here and I hope the project well. I would love to see object/hierarchical result set support grow. SQL ORMs feel so kludgy.
once you reduce all that to object traversal all your options are lost, your only entry point is the entity and the only connections are direct paths
it's not the underlying query language, it's the flattening to object
SQL and it's implementations do not support nested relations. The parent is suggesting that e.g. nested relations would enable better ORM solutions.
parent was right that hierarchical queries are not well supported, but that's not the same as outright using nested relations; also if you're not going to store data following normal forms for convenience no wonder sql is going to have a hard time querying it.
at which point you're better off with an object storage and a searchable index to the side anyway