At some point in their career the problem they're trying to solve will overwhelm even their own abilities - it just hasn't happened yet, but when it does, they'll be in for a reckoning.
All of the tooling, and processes, documentation, and code modularization that it takes us mortals to build complex things - this guy likely does in his sleep without it, until there's a problem he'll face where he can't anymore. He hasn't learned the curse of the gifted. You might have met this guy in high school - didn't need to study for his tests, aced most of his classes, then he specialized in college and ran into trouble because he never bothered to build such rigor into what he set out to achieve, it came naturally - and the longer that problem occurs the harder it becomes to learn the kinds of things that us mere mortals require.
My advice, if you can't manage him in house, manage him out
All of the tooling, and processes, documentation, and code modularization that it takes us mortals to build complex things - this guy likely does in his sleep without it, until there's a problem he'll face where he can't anymore. He hasn't learned the curse of the gifted. You might have met this guy in high school - didn't need to study for his tests, aced most of his classes, then he specialized in college and ran into trouble because he never bothered to build such rigor into what he set out to achieve, it came naturally - and the longer that problem occurs the harder it becomes to learn the kinds of things that us mere mortals require.
My advice, if you can't manage him in house, manage him out