I would respectfully disagree that open core doesn’t work - companies like Confluent, Databricks, MongoDB have shown that you can succeed with open core. DGraph I think tried to do too much rather than focusing on graph databases, which caused the commercial product to fail.
I think an issue with dgraph is their "open core" didn't include a lot of things you'd expect in a "core" DB (iirc backups, multi tenancy & acl). I'm not familiar with confluent & co. but imo for "open core" to succeed you need a product attractive enough to gain market share, and then you can have extra features for commercial use. But then why not just make it completely open source to gain even more market share and offer support contracts (eg redhat & co)?
