People with Dunning-Kruger symptoms (The think they are better than what they really are ) can go only so far, until they get fired if they can't get the job done. More like Peter's principle. On the other hand, I think I see what you're saying here...if a moron is always happy then I want to be one ??
You get to choose whether or not you want to be happy.
I don't know that morons are always happy. Sometimes they know on some level that they are morons and that makes them insecure and fearful and full of bluster and prone to gaslighting others and furiously projecting on them in order to save face.
It's usually also unfair to call them morons. I think people who behave moronically often have just as much mental potential and resources as anyone, but parts of it are blocked by various forms of fear and ignorance and limiting ideology. I guess you can argue that if someone walks, quacks and smells like a moron, they are one ... but it diminishes me to think of them as "less than", and besides, if they really are mentally limited then it's wrong to despise them for something they have no control over.
Often, the real reason we are disgusted with people who think they're better than they really are, is because that means they think that we're not as good as them. If we are secure in ourselves and have an actual personal "center", this should not impress us though.