I don't think people have discovered all the obvious stuff. Not even remotely. Sometimes, truth is hiding in plain sight. Of the 8 billion people who live on planet earth now, very few are intellectually capable of spotting something like this. And even they don't always do immediately. I think it's very likely that there is still tons of stuff like this hiding in plain sight, just with nobody around who made the right conclusions, especially in countries with little scientific infrastructure, like parts of Africa or central Asia.