I have worked with many knowledge hoarders.
Being a misunderstood genius or a difficult to emulate subject matter expert is one thing. The thing which makes it deadly is knowledge hoarding.
No project should tolerate knowledge hoarding at any time.
Silence likes a cancer grows.
In my time as a “mad genius” [called as much by my supervisor], I always maintained an interest in code reviews, in teaching colleagues of all experience levels and backgrounds about the tools I was developing, and, ultimately, creating software which did not need developers to configure it [could easily be given forms and handed to non-tech business users to use].
I was bewildered when the business did not take the APIs I built and drop them into forms so I would no longer be needed as a developer on that project.
Mad geniuses cannot exist without leaders who don’t know team management.
Rick, without a doubt, was an asshole, not an Einstein.