Two things I think: it ultimately doesn't matter, because the key differentiator between RDBMS selection is the management system, not the query system And sec

Two things I think: it ultimately doesn't matter, because the key differentiator between RDBMS selection is the management system, not the query system And second is that RDBMS's are historically closed-source enterprise tooling -- the vendors themselves have little interest rocking the boat, and there's not much freedom for the community to inject a new language into the system (except as ad-hoc, wonky transpilers, or framework wrappers like ORMs)