He's talking about the very common phenomenon of thinking you are a scientist when you're really just a crank (or you've become one). And this has to be read in

He's talking about the very common phenomenon of thinking you are a scientist when you're really just a crank (or you've become one). And this has to be read in the context of all of the previous points, which are about being an effective researcher or communicator. If truly no one recognizes "the importance of your work and the genius of your ideas", I suppose it's possible that the whole world is wrong and you're a misunderstood genius, but it's more likely that your work is not as valuable as you think it is and it is time to do something else.