Product Manager for MySQL here. Yes, I agree with you that the reason is most likely support. Consider SQL; it's declarative and highly expressive. Your user

Product Manager for MySQL here. Yes, I agree with you that the reason is most likely support. Consider SQL; it's declarative and highly expressive. Your users can craft queries that you did not consider, and you have to make sure they work consistently between versions. It's a very hard problem. Creating more public APIs? It's a hard sell that vendors are sensitive to. Reducing the surface area makes it easier to add future improvements.