This is a good take, and historically accurate IMO. Rule engines were indeed marketed as a more practical way of getting the benefits of declarative rules, in a form where supposedly non-programmers would be able to maintain the rule base. And yes, the relational model (in the unattractive guise of SQL) won out in the database space.

Just like functional languages inspire people to write "more functional" code in other languages, I think Prolog can inspire us to think in relations (SQL) and rules. Rules engines grew into monstrosities, but more light-weight rule engines exist and can be a great tool.