I'm yet to see evidence that the types of people who whinge about these types of "brilliant programmers" are themselves much better at documentation, training and onboarding a team. The fact that devs like this are even in a position to whine and complain about their projects becoming unmaintainable after the star team mate leaves is a clear demonstration that they themselves have not made any substantial contribution to the maintainability or transferability of the codebase. Further, it shows they lacked the ability to professionally advocate for these things within the business.

I'm very skeptical about these situational anecdotes where someone with low impact complains about someone with high impact. "I was on a team where the guy who wrote everything left and then everything sucked" is not a compelling vantage point.