I've lost count of how many columnar SQL databases have been donated to the apache project and there are so many systems like Actian and Alteryx where data analysts hook together relational operators with boxes and lines.

I had a prototype of a stream processing engine that passed RDF graphs along the lines between the boxes that enable an "object-relational" model, you could eliminate the need for hard-to-maintain joins but I found that firms that had bought multiple columnar processing database companies believed in performance at all cost and couldn't care less for any system that couldn't be implemented with SIMD instructions.