I am not sure this counts as an "obvious truth" in that there's a lot of nuance going on that can be quibbled with.RPG systems do gameplay, not genre. Seeking out a "space opera RPG" without specifying what kind of gameplay you envision is about as useful as seeking out a "space opera video game" without specifying shooter, platformer, fighter, etc.
That is why it is good to express them publicly.Obvious truths are often not obvious outside your own head.