To me, that's kind-of like saying the MacBook Air is a competitor to Apple's flagship MacBook Pro. They're two different products, made by the same company, doing pretty much the same thing but designed for different use cases. It's the way I always felt about Oracle vs. MySQL, even back before Oracle owned MySQL, that they are two different RDBMS platforms designed for two different use cases.

These days, that line may be blurred a little bit, and you can see how both paradigms (and more!) can be combined into a single product with PostgreSQL, but I feel like the MacBook analogy really sums up the way I feel about these two systems.